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  • whats wrong with strcpy()

    - by blacktooth
    What is wrong with strcpy() in this code? void process_filedata(char *filename) { void* content; const char * buffer; char * temp; char * row; char * col; int lsize,buflen,tmp,num_scan; //num_scan - number of characters scanned int m=0,p=0,d=0,j=0; //m - machine, p - phase, d- delimiter, j - job FILE *file_pointer = fopen("machinetimesnew.csv","r"); if(file_pointer == NULL) { error_flag = print_error("Error opening file"); if(error_flag) exit(1); } fseek(file_pointer, 0 ,SEEK_END); lsize = ftell(file_pointer); buflen = lsize; rewind(file_pointer); // content = (char*) malloc(sizeof(char)*lsize); fread(content,1,lsize,file_pointer); buffer = (const char*) content; strcpy(temp,buffer); row = strtok(temp,"\n"); ............... ............... I am getting a segmentation fault..

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  • I can't find the homepage for my ASP.NET MVC site :(

    - by Pure.Krome
    Hi folks, really simple question here. when I remove the default route, I returns an empty page to the browser :- routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); Now before everyone starts shouting "that's because that's the default route to access all action methods, etc.." .. i know that. My question is - what code / routes does the default framework try and call .. which makes that Default Route get used/kick in? Why? I don't wish to make that my default route regex (don't ask why - this is some R&D) but I still need the main home page .. ie. Home/Index . If i try and just add that route, it doesn't get called and an empty page is returned. So -- what does the framework try and call when a user doesn't provide any urls? It's like there's some secret default document stuff set up? Cheers :)

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  • Using ddply() to Get Frequency of Certain IDs, by Appearance in Multiple Rows (in R)

    - by EconomiCurtis
    Goal If the following description is hard follow, please see the example "before" and "after" to see a straightforward example. I have bartering data, with unique trade ids, and two sides of the trade. Side1 and Side2 are baskets, lists of item ids that represent both sides of the barter transaction. I'd like to count the frequency each ITEM appears in TRADES. E.g, if item "001" appeared in 3 trades, I'd have a count of 3 (ignoring how many times the item appeared in each trade). Further, I'd like to do this with the plyr ddply function. (If you're interested as to my motivation, I working over many hundreds of thousands of transactions and am already using a ddply to calculate several other summary statistics. I'd like to add this to the ddply I'm already using, rather than calculate it after, and merge it into the ddply output.... sorry if that was difficult to follow.) In terms of pseudo code I'm working off of: merge each row of Side1 and Side2 by row, get unique() appearances of each item id apply table() function transpose and relabel output from table Example of the structure of my data, and the output I desire. Data Example (before): df <- data.frame(TradeID = c("01","02","03","04")) df$Side1 = list(c("001","001","002"), c("002","002","003"), c("001","004"), c("001","002","003","004")) df$Side2 = list(c("001"),c("007"),c("009"),c()) Desired Output (after): df.ItemRelFreq_byTradeID <- data.frame(ItemID = c("001","002","003","004","007","009"), RelFreq_byTrade = c(3,3,2,2,1,1)) One method to do this without ddply I've worked out one way to do this below. My problem is that I can't quite seem to get ddply to do this for me. temp <- table(unlist(sapply(mapply(c,df$Side1,df$Side2), unique))) df.ItemRelFreq_byTradeID <- data.frame(ItemID = names(temp), RelFreq_byTrade = temp[]) Thanks for any help you can offer! Curtis

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  • ASP.NET 'Check all checkboxes' control

    - by RUiHAO
    I am using visual studio 2005 c#, and doing server side coding. I have a list of checkboxes in my gridview via checkbox template. I have tried to assign a checkbox in my header template, and assigned a checkbox_checkchange method to make it such that when the checkbox at the header is checked, the list of checkboxes in the template will be checked as well. However, it does not work and I am not able to spot the mistake. Below is my code for my checkbox in header template: protected void CheckAllCB_CheckedChanged(object sender, EventArgs e) { CheckBox chk = (CheckBox)GridView1.HeaderRow.FindControl("CheckAll"); if (chk.Checked) { for (int i = 0; i < GridView1.Rows.Count; i++) { CheckBox chkrow = (CheckBox)GridView1.Rows[i].FindControl("UserSelector"); chkrow.Checked = true; } } else { for (int i = 0; i < GridView1.Rows.Count; i++) { CheckBox chkrow = (CheckBox)GridView1.Rows[i].FindControl("UserSelector"); chkrow.Checked = false; } } } Thus I tried using a button to assign the checkall command instead. However, when I clicked on the button, the page does nothing but just refreshes itself. Below is my code for the checkall and uncheckall button: private void ToggleCheckState(bool checkState) { // Iterate through the Products.Rows property foreach (GridViewRow row in GridView1.Rows) { // Access the CheckBox CheckBox cb = (CheckBox)row.FindControl("UserSelector"); if (cb != null) cb.Checked = checkState; } } protected void CheckAll_Click(object sender, EventArgs e) { ToggleCheckState(true); } protected void UncheckAll_Click(object sender, EventArgs e) { ToggleCheckState(false); } Anyone can help me identify the mistake I did in my method? Thank you UserSelection GridView template:

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  • Cannot Display Data from MySQL table

    - by MxmastaMills
    I've got a pretty standard call to a MySQL database and for some reason I can't get the code to work. Here's what I have: $mysqli = mysqli_connect("localhost","username","password"); if (!$mysqli) { die('Could not connect: ' . mysqli_error($mysqli)); } session_start(); $sql = "SELECT * FROM jobs ORDER BY id DESC"; $result = $mysqli->query($sql); $num_rows = mysqli_num_rows($result); Now, first, I know that it is connecting properly because I'm not getting the die method plus I added an else conditional in there previously and it checked out. Then the page displays but I get the errors: Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in blablabla/index.php on line 11 Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, boolean given in blablabla/index.php on line 12 I've double-checked my database and there is a table called jobs with a row of "id" (it's the primary row). The thing that confuses me is this is code that I literally copied and pasted from another site I built and for some reason the code doesn't work on this one (I obviously copy and pasted it and then just changed the table name and rows accordingly). I saw the error and tried: $num_rows = $mysqli_result->num_rows; $row_array = $mysqli_result->fetch_array; and that fixed the errors but resulted in no data being passed (because obviously $mysqli_result has no value). I don't know why the error is calling for that (is it a difference in version of MySQL or PHP from the other site)? Can someone help me track down the problem? Thanks so much. Sorry if it's something super simple that I'm overlooking, I've been at it for a while.

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  • MySQL Table Loop using PHP

    - by JM4
    I have an online form which collects consumer data and stores in a dedicated MySQL database. In some instances, data is passed in the URL under the "RefID" variable which is also stored in the database and attached to each registration. I use the 'mysql_num_rows ($result)' to fetch all agent details on another page but this only returns ALL available details. My goal is as follows: GOAL I want to create an HTML table in which rows are automatically generated based on the list of all registrations on my site. A new row is created IF and ONLY IF a unique RefID is present on that particular record. In the event the field is NULL, it is reported on a single line. In short, the HTML table could look something like this: RefID - Number of Enrollments abc123 - 10 baseball - 11 twonk - 7 NULL - 33 Where abc123 is a particular RefID and 10 is the number of times that RefID appears in the DB. If a new registration comes in with RefID = "horses", a new row is created, showing "horses - 1". The HTML table will be viewable by account administrators needing to see the number of enrollments for a particular RefID (which they won't know ahead of time). Anybody have any suggestions?

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  • Why does this sql statement keep saying it is a boolean and not a parameter? (php/Mysql)

    - by ggfan
    In this statement, I am trying to see if there if the latest posting in the database that has the exact same title, price, city, state, detail. If there is, then it would say to the user that the exact post has been already made; if not then insert the posting into the dbc. (This is one type of check so that users can't accidentally post twice. This may not be the best check, but this statement error is annoying me, so I want it to work :)) Why won't this sql work? I think it's not letting the title=$title and not getting the value in the $title... ERROR: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in postad.php on line 365 //there is a form that users fill out that has title, price, city, etc <form> blah blah </form> //if users click submit, then does all the checks and if all okay, insert to dbc if (isset($_POST['submit'])) { // Grab the pposting data from the POST and gets rid of any funny stuff $title = mysqli_real_escape_string($dbc, trim($_POST['title'])); $price = mysqli_real_escape_string($dbc, trim($_POST['price'])); $city = mysqli_real_escape_string($dbc, trim($_POST['city'])); $state = mysqli_real_escape_string($dbc, trim($_POST['state'])); $detail = mysqli_real_escape_string($dbc, trim($_POST['detail'])); if (!is_numeric($price) && !empty($price)) { echo "<p class='error'>The price can only be numbers. No special characters, etc</p>"; } //Error problem...won't let me set title=$title, detail=$detail, etc. //this statement after all the checks so that none of the variables are empty $query="Select * FROM posting WHERE user_id={$_SESSION['user_id']} AND title=$title AND price=$price AND city=$city AND state=$state AND detail=$detail"; $data = mysqli_query($dbc, $query); if(mysqli_num_rows($data)==1) { echo "You already posted this ad. Most likely caused by refreshing too many times."; } }

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  • UITableView which has sections as alphabets and various rows within each section

    - by lifemoves
    Hello I have a database in which I am inserting data by parsing an XML document. Populating the data using Navigation bar control view. I have various NSObjects defined in a class and have populated the data using NSMutableArray. Using UITableview I have populated the data. My question is : I have populated the data with the sections defined in it as alphabets so I have total of 26 sections. Each section has data in form of name. Now when I use cellforrowatIndexpath it does not give me the correct index for row and section together. My code is : (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } /* Index names as in AB ....Z */ NSString *strIndexNames = [arrCharacters objectAtIndex:indexPath.section]; /* object sections has names in each section */ NSArray *arrIndexedCategories = [objSections objectForKey:strIndexNames]; NSString *strName = [arrIndexedCategories objectAtIndex:indexPath.row] ; cell.textLabel.text = strName; cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; cell.textLabel.font = [UIFont systemFontOfSize:16]; return cell; } Any help whatsoever will be really helpful. S

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  • How to limit a user to entering 10 keywords or less using PHP & MySQL?

    - by G4TV
    I'm trying to limit my users to entering at least 10 keywords and was wondering how would I be able to do this using PHP & MySQL with my current Keyword script? Here is the add keywords PHP MySQL code. if (isset($_POST['tag']) && trim($_POST['tag'])!=='') { $tags = explode(",", $_POST['tag']); for ($x = 0; $x < count($tags); $x++){ $mysqli = mysqli_connect("localhost", "root", "", "sitename"); $query1 = "INSERT INTO tags (tag) VALUES ('" . mysqli_real_escape_string($mysqli, strtolower(htmlentities(trim(strip_tags($tags[$x]))))) . "')"; if (!mysqli_query($mysqli, $query1)) { print mysqli_error($mysqli); return; } $mysqli = mysqli_connect("localhost", "root", "", "sitename"); $dbc = mysqli_query($mysqli,"SELECT id FROM tags WHERE tag='" . mysqli_real_escape_string($mysqli, strtolower(htmlentities(trim(strip_tags($tags[$x]))))) . "'"); if (!$dbc) { print mysqli_error($mysqli); } else { while($row = mysqli_fetch_array($dbc)){ $id = $row["id"]; } } $query2 = "INSERT INTO question_tags (tag_id, question_id, user_id, date_created) VALUES ('$id', '$question', '$user', NOW())"; if (!mysqli_query($mysqli, $query2)) { print mysqli_error($mysqli); return; } } }

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  • login using UITableView

    - by EquinoX
    How can I create a login for username/password just like in the skype application? I know it's a grouped table view.. but how can I do that? I searched the site and found the following code: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; UILabel *startDtLbl = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 80, 25)]; if (indexPath.row == 0) startDtLbl.text = @"Username"; else { startDtLbl.text = @"Password"; } startDtLbl.backgroundColor = [UIColor clearColor]; [cell.contentView addSubview:startDtLbl]; UITextField *passwordTF = [[UITextField alloc] initWithFrame:CGRectMake(100, 5, 200, 35)]; passwordTF.delegate = self; if (indexPath.row == 0) passwordTF.tag = 0; else { passwordTF.tag = 1; } [cell.contentView addSubview:passwordTF]; } return cell; } When I do: NSString * username = [((UITextField*)[self.view viewWithTag:0]) text]; NSString * password = [((UITextField*)[self.view viewWithTag:1]) text]; it gives me this error: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIView text]: unrecognized selector sent to instance 0x6c3c600 Why is this?

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  • Javascript dynamic table memory usage

    - by Dan
    I use a dynamic table: <html> <body> <button id="button">Build table</button> <div id="container"> <script type="text/javascript"> window.onload=function(){ var table = null; var row = "<tr><td>111111111111111111111111111111111111111111111111111111</td>" + "<td>222222222222222222222222222222222222222222222222222222</td>" + "<td>333333333333333333333333333333333333333333333333333333</td></tr>"; var data = null; for (var i = 0; i < 2000; i++){ data += row; } var obj = document.getElementById("button"); obj.onclick=function buildTable(){ document.getElementById("container").innerHTML = "<div><table><tbody>" + data + "</tbody></table></div>"; }; }; </script> </body> </html> Using chromes task manager, each time new data is loaded the memory usage increases considerably and doesn't go down, so after some time the app consumes a lot of memory and requires the browser to be closed. Is there any change in the code I can use to solve this or is it a browser side problem?

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  • A better way of handling the below program(may be with Take/Skip/TakeWhile.. or anything better)

    - by Newbie
    I have a data table which has only one row. But it is having 44 columns. My task is to get the columns from the 4th row till the end. Henceforth, I have done the below program that suits my requirement. (kindly note that dt is the datatable) List<decimal> lstDr = new List<decimal>(); Enumerable.Range(0, dt.Columns.Count).ToList().ForEach(i => { if (i > 3) lstDr.Add(Convert.ToDecimal(dt.Rows[0][i])); } ); There is nothing harm in the program. Works fine. But I feel that there may be a better way of handimg the program may be with Skip ot Take or TakeWhile or anyother stuff. I am looking for a better solution that the one I implemented. Is it possible? I am using c#3.0 Thanks.

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  • UserControlArray in Specific ButtonControlArray in C#

    - by Phanindar
    I am new to C#.I have been thinking of adding a ButtonControlArray where i can store each button control.Here is part of my code.I am creating a 6*6 array of button Control. ButtonControl buttonControl; ButtonControl[,] arrayButtons = new ButtonControl[6,6]; public void createGrid() { l = 0; for (int i = 0; i < numberOfButtons; i++) { for (int k = 0; k < numberOfButtons; k++) { buttonControl = new ButtonControl(); buttonControl.Location = new Point(l,j); j += 55; arrayButtons[i, k] = buttonControl; //After the above statement if i print Console.WriteLine(""+arrayButtons[i,k]); i am getting only my projectname.buttoncontrol myGridControl.Controls.Add(buttonControl); } l += 55; j = 10; } } I want to access each variable in arrayButtons[][]..like in a 3*3 matrix..if i want 2nd row 1 column element..then i get something like arrayname[2][1]..same way if i want 2nd button in 2nd row how can i get..i tried doing one way but i couldnt figure it out...Can you help me out with this..

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  • Questions about "sets"

    - by James
    I have a test tomorrow that I am revising for and the lecturer has supplied some sample questions with no answers. I was hoping I could get some help with a couple of them. I've written what I think the answer is for them. 1. What is the type of the set {1, 2, 3}? integer/number 2. What is the type of the set {{1}, {2}, {3}}? integer/number (unsure what putting each number in {} does?) 3. What is the type of the set {{1}, {2}, {3}, empty}? integer/number 4. What is the type of the set {1, {2}, 3}? — is it well typed? integer/number 5. What is the type of the set {1, 2, john}? — is it well typed? unsure for a mixed set. Taking a complete guess of void or empty. Any help will be much appreciated.

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  • Oracle Blob as img src in PHP page

    - by menkes
    I have a site that currently uses images on a file server. The images appear on a page where the user can drag and drop each as is needed. This is done with jQuery and the images are enclosed in a list. Each image is pretty standard: <img src='//network_path/image.png' height='80px'> Now however I need to reference images stored as a BLOB in an Oracle database (no choice on this, so not a merit discussion). I have no problem retrieving the BLOB and displaying on it's own using: $sql = "SELECT image FROM images WHERE image_id = 123"; $stid = oci_parse($conn, $sql); oci_execute($stid); $row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS); $img = $row['IMAGE']->load(); header("Content-type: image/jpeg"); print $img; But I need to [efficiently] get that image as the src attribute of the img tag. I tried imagecreatefromstring() but that just returns the image in the browser, ignoring the other html. I looked at data uri, but the IE8 size limit rules that out. So now I am kind of stuck. My searches keep coming up with using a src attribute that loads another page that contains the image. But I need the image itself to actually show on the page. (Note: I say image, meaning at least one image but as many as eight on a page). Any help would be greatly appreciated.

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  • ASP.Net MVC 2 Auto Complete Textbox With Custom View Model Attribute & EditorTemplate

    - by SeanMcAlinden
    In this post I’m going to show how to create a generic, ajax driven Auto Complete text box using the new MVC 2 Templates and the jQuery UI library. The template will be automatically displayed when a property is decorated with a custom attribute within the view model. The AutoComplete text box in action will look like the following:   The first thing to do is to do is visit my previous blog post to put the custom model metadata provider in place, this is necessary when using custom attributes on the view model. http://weblogs.asp.net/seanmcalinden/archive/2010/06/11/custom-asp-net-mvc-2-modelmetadataprovider-for-using-custom-view-model-attributes.aspx Once this is in place, make sure you visit the jQuery UI and download the latest stable release – in this example I’m using version 1.8.2. You can download it here. Add the jQuery scripts and css theme to your project and add references to them in your master page. Should look something like the following: Site.Master <head runat="server">     <title><asp:ContentPlaceHolder ID="TitleContent" runat="server" /></title>     <link href="../../Content/Site.css" rel="stylesheet" type="text/css" />     <link href="../../css/ui-lightness/jquery-ui-1.8.2.custom.css" rel="stylesheet" type="text/css" />     <script src="../../Scripts/jquery-1.4.2.min.js" type="text/javascript"></script>     <script src="../../Scripts/jquery-ui-1.8.2.custom.min.js" type="text/javascript"></script> </head> Once this is place we can get started. Creating the AutoComplete Custom Attribute The auto complete attribute will derive from the abstract MetadataAttribute created in my previous post. It will look like the following: AutoCompleteAttribute using System.Collections.Generic; using System.Web.Mvc; using System.Web.Routing; namespace Mvc2Templates.Attributes {     public class AutoCompleteAttribute : MetadataAttribute     {         public RouteValueDictionary RouteValueDictionary;         public AutoCompleteAttribute(string controller, string action, string parameterName)         {             this.RouteValueDictionary = new RouteValueDictionary();             this.RouteValueDictionary.Add("Controller", controller);             this.RouteValueDictionary.Add("Action", action);             this.RouteValueDictionary.Add(parameterName, string.Empty);         }         public override void Process(ModelMetadata modelMetaData)         {             modelMetaData.AdditionalValues.Add("AutoCompleteUrlData", this.RouteValueDictionary);             modelMetaData.TemplateHint = "AutoComplete";         }     } } As you can see, the constructor takes in strings for the controller, action and parameter name. The parameter name will be used for passing the search text within the auto complete text box. The constructor then creates a new RouteValueDictionary which we will use later to construct the url for getting the auto complete results via ajax. The main interesting method is the method override called Process. With the process method, the route value dictionary is added to the modelMetaData AdditionalValues collection. The TemplateHint is also set to AutoComplete, this means that when the view model is parsed for display, the MVC 2 framework will look for a view user control template called AutoComplete, if it finds one, it uses that template to display the property. The View Model To show you how the attribute will look, this is the view model I have used in my example which can be downloaded at the end of this post. View Model using System.ComponentModel; using Mvc2Templates.Attributes; namespace Mvc2Templates.Models {     public class TemplateDemoViewModel     {         [AutoComplete("Home", "AutoCompleteResult", "searchText")]         [DisplayName("European Country Search")]         public string SearchText { get; set; }     } } As you can see, the auto complete attribute is called with the controller name, action name and the name of the action parameter that the search text will be passed into. The AutoComplete Template Now all of this is in place, it’s time to create the AutoComplete template. Create a ViewUserControl called AutoComplete.ascx at the following location within your application – Views/Shared/EditorTemplates/AutoComplete.ascx Add the following code: AutoComplete.ascx <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %> <%     var propertyName = ViewData.ModelMetadata.PropertyName;     var propertyValue = ViewData.ModelMetadata.Model;     var id = Guid.NewGuid().ToString();     RouteValueDictionary urlData =         (RouteValueDictionary)ViewData.ModelMetadata.AdditionalValues.Where(x => x.Key == "AutoCompleteUrlData").Single().Value;     var url = Mvc2Templates.Views.Shared.Helpers.RouteHelper.GetUrl(this.ViewContext.RequestContext, urlData); %> <input type="text" name="<%= propertyName %>" value="<%= propertyValue %>" id="<%= id %>" class="autoComplete" /> <script type="text/javascript">     $(function () {         $("#<%= id %>").autocomplete({             source: function (request, response) {                 $.ajax({                     url: "<%= url %>" + request.term,                     dataType: "json",                     success: function (data) {                         response(data);                     }                 });             },             minLength: 2         });     }); </script> There is a lot going on in here but when you break it down it’s quite simple. Firstly, the property name and property value are retrieved through the model meta data. These are required to ensure that the text box input has the correct name and data to allow for model binding. If you look at line 14 you can see them being used in the text box input creation. The interesting bit is on line 8 and 9, this is the code to retrieve the route value dictionary we added into the model metada via the custom attribute. Line 11 is used to create the url, in order to do this I created a quick helper class which looks like the code below titled RouteHelper. The last bit of script is the code to initialise the jQuery UI AutoComplete control with the correct url for calling back to our controller action. RouteHelper using System.Web.Mvc; using System.Web.Routing; namespace Mvc2Templates.Views.Shared.Helpers {     public static class RouteHelper     {         const string Controller = "Controller";         const string Action = "Action";         const string ReplaceFormatString = "REPLACE{0}";         public static string GetUrl(RequestContext requestContext, RouteValueDictionary routeValueDictionary)         {             RouteValueDictionary urlData = new RouteValueDictionary();             UrlHelper urlHelper = new UrlHelper(requestContext);                          int i = 0;             foreach(var item in routeValueDictionary)             {                 if (item.Value == string.Empty)                 {                     i++;                     urlData.Add(item.Key, string.Format(ReplaceFormatString, i.ToString()));                 }                 else                 {                     urlData.Add(item.Key, item.Value);                 }             }             var url = urlHelper.RouteUrl(urlData);             for (int index = 1; index <= i; index++)             {                 url = url.Replace(string.Format(ReplaceFormatString, index.ToString()), string.Empty);             }             return url;         }     } } See it in action All you need to do to see it in action is pass a view model from your controller with the new AutoComplete attribute attached and call the following within your view: <%= this.Html.EditorForModel() %> NOTE: The jQuery UI auto complete control expects a JSON string returned from your controller action method… as you can’t use the JsonResult to perform GET requests, use a normal action result, convert your data into json and return it as a string via a ContentResult. If you download the solution it will be very clear how to handle the controller and action for this demo. The full source code for this post can be downloaded here. It has been developed using MVC 2 and Visual Studio 2010. As always, I hope this has been interesting/useful. Kind Regards, Sean McAlinden.

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  • Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

    - by mortezam
    This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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  • Getting Started Building Windows 8 Store Apps with XAML/C#

    - by dwahlin
    Technology is fun isn’t it? As soon as you think you’ve figured out where things are heading a new technology comes onto the scene, changes things up, and offers new opportunities. One of the new technologies I’ve been spending quite a bit of time with lately is Windows 8 store applications. I posted my thoughts about Windows 8 during the BUILD conference in 2011 and still feel excited about the opportunity there. Time will tell how well it ends up being accepted by consumers but I’m hopeful that it’ll take off. I currently have two Windows 8 store application concepts I’m working on with one being built in XAML/C# and another in HTML/JavaScript. I really like that Microsoft supports both options since it caters to a variety of developers and makes it easy to get started regardless if you’re a desktop developer or Web developer. Here’s a quick look at how the technologies are organized in Windows 8: In this post I’ll focus on the basics of Windows 8 store XAML/C# apps by looking at features, files, and code provided by Visual Studio projects. To get started building these types of apps you’ll definitely need to have some knowledge of XAML and C#. Let’s get started by looking at the Windows 8 store project types available in Visual Studio 2012.   Windows 8 Store XAML/C# Project Types When you open Visual Studio 2012 you’ll see a new entry under C# named Windows Store. It includes 6 different project types as shown next.   The Blank App project provides initial starter code and a single page whereas the Grid App and Split App templates provide quite a bit more code as well as multiple pages for your application. The other projects available can be be used to create a class library project that runs in Windows 8 store apps, a WinRT component such as a custom control, and a unit test library project respectively. If you’re building an application that displays data in groups using the “tile” concept then the Grid App or Split App project templates are a good place to start. An example of the initial screens generated by each project is shown next: Grid App Split View App   When a user clicks a tile in a Grid App they can view details about the tile data. With a Split View app groups/categories are shown and when the user clicks on a group they can see a list of all the different items and then drill-down into them:   For the remainder of this post I’ll focus on functionality provided by the Blank App project since it provides a simple way to get started learning the fundamentals of building Windows 8 store apps.   Blank App Project Walkthrough The Blank App project is a great place to start since it’s simple and lets you focus on the basics. In this post I’ll focus on what it provides you out of the box and cover additional details in future posts. Once you have the basics down you can move to the other project types if you need the functionality they provide. The Blank App project template does exactly what it says – you get an empty project with a few starter files added to help get you going. This is a good option if you’ll be building an app that doesn’t fit into the grid layout view that you see a lot of Windows 8 store apps following (such as on the Windows 8 start screen). I ended up starting with the Blank App project template for the app I’m currently working on since I’m not displaying data/image tiles (something the Grid App project does well) or drilling down into lists of data (functionality that the Split App project provides). The Blank App project provides images for the tiles and splash screen (you’ll definitely want to change these), a StandardStyles.xaml resource dictionary that includes a lot of helpful styles such as buttons for the AppBar (a special type of menu in Windows 8 store apps), an App.xaml file, and the app’s main page which is named MainPage.xaml. It also adds a Package.appxmanifest that is used to define functionality that your app requires, app information used in the store, plus more. The App.xaml, App.xaml.cs and StandardStyles.xaml Files The App.xaml file handles loading a resource dictionary named StandardStyles.xaml which has several key styles used throughout the application: <Application x:Class="BlankApp.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="using:BlankApp"> <Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <!-- Styles that define common aspects of the platform look and feel Required by Visual Studio project and item templates --> <ResourceDictionary Source="Common/StandardStyles.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Application.Resources> </Application>   StandardStyles.xaml has style definitions for different text styles and AppBar buttons. If you scroll down toward the middle of the file you’ll see that many AppBar button styles are included such as one for an edit icon. Button styles like this can be used to quickly and easily add icons/buttons into your application without having to be an expert in design. <Style x:Key="EditAppBarButtonStyle" TargetType="ButtonBase" BasedOn="{StaticResource AppBarButtonStyle}"> <Setter Property="AutomationProperties.AutomationId" Value="EditAppBarButton"/> <Setter Property="AutomationProperties.Name" Value="Edit"/> <Setter Property="Content" Value="&#xE104;"/> </Style> Switching over to App.xaml.cs, it includes some code to help get you started. An OnLaunched() method is added to handle creating a Frame that child pages such as MainPage.xaml can be loaded into. The Frame has the same overall purpose as the one found in WPF and Silverlight applications - it’s used to navigate between pages in an application. /// <summary> /// Invoked when the application is launched normally by the end user. Other entry points /// will be used when the application is launched to open a specific file, to display /// search results, and so forth. /// </summary> /// <param name="args">Details about the launch request and process.</param> protected override void OnLaunched(LaunchActivatedEventArgs args) { Frame rootFrame = Window.Current.Content as Frame; // Do not repeat app initialization when the Window already has content, // just ensure that the window is active if (rootFrame == null) { // Create a Frame to act as the navigation context and navigate to the first page rootFrame = new Frame(); if (args.PreviousExecutionState == ApplicationExecutionState.Terminated) { //TODO: Load state from previously suspended application } // Place the frame in the current Window Window.Current.Content = rootFrame; } if (rootFrame.Content == null) { // When the navigation stack isn't restored navigate to the first page, // configuring the new page by passing required information as a navigation // parameter if (!rootFrame.Navigate(typeof(MainPage), args.Arguments)) { throw new Exception("Failed to create initial page"); } } // Ensure the current window is active Window.Current.Activate(); }   Notice that in addition to creating a Frame the code also checks to see if the app was previously terminated so that you can load any state/data that the user may need when the app is launched again. If you’re new to the lifecycle of Windows 8 store apps the following image shows how an app can be running, suspended, and terminated.   If the user switches from an app they’re running the app will be suspended in memory. The app may stay suspended or may be terminated depending on how much memory the OS thinks it needs so it’s important to save state in case the application is ultimately terminated and has to be started fresh. Although I won’t cover saving application state here, additional information can be found at http://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh465099.aspx. Another method in App.xaml.cs named OnSuspending() is also included in App.xaml.cs that can be used to store state as the user switches to another application:   /// <summary> /// Invoked when application execution is being suspended. Application state is saved /// without knowing whether the application will be terminated or resumed with the contents /// of memory still intact. /// </summary> /// <param name="sender">The source of the suspend request.</param> /// <param name="e">Details about the suspend request.</param> private void OnSuspending(object sender, SuspendingEventArgs e) { var deferral = e.SuspendingOperation.GetDeferral(); //TODO: Save application state and stop any background activity deferral.Complete(); } The MainPage.xaml and MainPage.xaml.cs Files The Blank App project adds a file named MainPage.xaml that acts as the initial screen for the application. It doesn’t include anything aside from an empty <Grid> XAML element in it. The code-behind class named MainPage.xaml.cs includes a constructor as well as a method named OnNavigatedTo() that is called once the page is displayed in the frame.   /// <summary> /// An empty page that can be used on its own or navigated to within a Frame. /// </summary> public sealed partial class MainPage : Page { public MainPage() { this.InitializeComponent(); } /// <summary> /// Invoked when this page is about to be displayed in a Frame. /// </summary> /// <param name="e">Event data that describes how this page was reached. The Parameter /// property is typically used to configure the page.</param> protected override void OnNavigatedTo(NavigationEventArgs e) { } }   If you’re experienced with XAML you can switch to Design mode and start dragging and dropping XAML controls from the ToolBox in Visual Studio. If you prefer to type XAML you can do that as well in the XAML editor or while in split mode. Many of the controls available in WPF and Silverlight are included such as Canvas, Grid, StackPanel, and Border for layout. Standard input controls are also included such as TextBox, CheckBox, PasswordBox, RadioButton, ComboBox, ListBox, and more. MediaElement is available for rendering video or playing audio files. Some of the “common” XAML controls included out of the box are shown next:   Although XAML/C# Windows 8 store apps don’t include all of the functionality available in Silverlight 5, the core functionality required to build store apps is there with additional functionality available in open source projects such as Callisto (started by Microsoft’s Tim Heuer), Q42.WinRT, and others. Standard XAML data binding can be used to bind C# objects to controls, converters can be used to manipulate data during the data binding process, and custom styles and templates can be applied to controls to modify them. Although Visual Studio 2012 doesn’t support visually creating styles or templates, Expression Blend 5 handles that very well. To get started building the initial screen of a Windows 8 app you can start adding controls as mentioned earlier. Simply place them inside of the <Grid> element that’s included. You can arrange controls in a stacked manner using the StackPanel control, add a border around controls using the Border control, arrange controls in columns and rows using the Grid control, or absolutely position controls using the Canvas control. One of the controls that may be new to you is the AppBar. It can be used to add menu/toolbar functionality into a store app and keep the app clean and focused. You can place an AppBar at the top or bottom of the screen. A user on a touch device can swipe up to display the bottom AppBar or right-click when using a mouse. An example of defining an AppBar that contains an Edit button is shown next. The EditAppBarButtonStyle is available in the StandardStyles.xaml file mentioned earlier. <Page.BottomAppBar> <AppBar x:Name="ApplicationAppBar" Padding="10,0,10,0" AutomationProperties.Name="Bottom App Bar"> <Grid> <StackPanel x:Name="RightPanel" Orientation="Horizontal" Grid.Column="1" HorizontalAlignment="Right"> <Button x:Name="Edit" Style="{StaticResource EditAppBarButtonStyle}" Tag="Edit" /> </StackPanel> </Grid> </AppBar> </Page.BottomAppBar> Like standard XAML controls, the <Button> control in the AppBar can be wired to an event handler method in the MainPage.Xaml.cs file or even bound to a ViewModel object using “commanding” if your app follows the Model-View-ViewModel (MVVM) pattern (check out the MVVM Light package available through NuGet if you’re using MVVM with Windows 8 store apps). The AppBar can be used to navigate to different screens, show and hide controls, display dialogs, show settings screens, and more.   The Package.appxmanifest File The Package.appxmanifest file contains configuration details about your Windows 8 store app. By double-clicking it in Visual Studio you can define the splash screen image, small and wide logo images used for tiles on the start screen, orientation information, and more. You can also define what capabilities the app has such as if it uses the Internet, supports geolocation functionality, requires a microphone or webcam, etc. App declarations such as background processes, file picker functionality, and sharing can also be defined Finally, information about how the app is packaged for deployment to the store can also be defined. Summary If you already have some experience working with XAML technologies you’ll find that getting started building Windows 8 applications is pretty straightforward. Many of the controls available in Silverlight and WPF are available making it easy to get started without having to relearn a lot of new technologies. In the next post in this series I’ll discuss additional features that can be used in your Windows 8 store apps.

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  • The Execute SQL Task

    In this article we are going to take you through the Execute SQL Task in SQL Server Integration Services for SQL Server 2005 (although it appies just as well to SQL Server 2008).  We will be covering all the essentials that you will need to know to effectively use this task and make it as flexible as possible. The things we will be looking at are as follows: A tour of the Task. The properties of the Task. After looking at these introductory topics we will then get into some examples. The examples will show different types of usage for the task: Returning a single value from a SQL query with two input parameters. Returning a rowset from a SQL query. Executing a stored procedure and retrieveing a rowset, a return value, an output parameter value and passing in an input parameter. Passing in the SQL Statement from a variable. Passing in the SQL Statement from a file. Tour Of The Task Before we can start to use the Execute SQL Task in our packages we are going to need to locate it in the toolbox. Let's do that now. Whilst in the Control Flow section of the package expand your toolbox and locate the Execute SQL Task. Below is how we found ours. Now drag the task onto the designer. As you can see from the following image we have a validation error appear telling us that no connection manager has been assigned to the task. This can be easily remedied by creating a connection manager. There are certain types of connection manager that are compatable with this task so we cannot just create any connection manager and these are detailed in a few graphics time. Double click on the task itself to take a look at the custom user interface provided to us for this task. The task will open on the general tab as shown below. Take a bit of time to have a look around here as throughout this article we will be revisting this page many times. Whilst on the general tab, drop down the combobox next to the ConnectionType property. In here you will see the types of connection manager which this task will accept. As with SQL Server 2000 DTS, SSIS allows you to output values from this task in a number of formats. Have a look at the combobox next to the Resultset property. The major difference here is the ability to output into XML. If you drop down the combobox next to the SQLSourceType property you will see the ways in which you can pass a SQL Statement into the task itself. We will have examples of each of these later on but certainly when we saw these for the first time we were very excited. Next to the SQLStatement property if you click in the empty box next to it you will see ellipses appear. Click on them and you will see the very basic query editor that becomes available to you. Alternatively after you have specified a connection manager for the task you can click on the Build Query button to bring up a completely different query editor. This is slightly inconsistent. Once you've finished looking around the general tab, move on to the next tab which is the parameter mapping tab. We shall, again, be visiting this tab throughout the article but to give you an initial heads up this is where you define the input, output and return values from your task. Note this is not where you specify the resultset. If however you now move on to the ResultSet tab this is where you define what variable will receive the output from your SQL Statement in whatever form that is. Property Expressions are one of the most amazing things to happen in SSIS and they will not be covered here as they deserve a whole article to themselves. Watch out for this as their usefulness will astound you. For a more detailed discussion of what should be the parameter markers in the SQL Statements on the General tab and how to map them to variables on the Parameter Mapping tab see Working with Parameters and Return Codes in the Execute SQL Task. Task Properties There are two places where you can specify the properties for your task. One is in the task UI itself and the other is in the property pane which will appear if you right click on your task and select Properties from the context menu. We will be doing plenty of property setting in the UI later so let's take a moment to have a look at the property pane. Below is a graphic showing our properties pane. Now we shall take you through all the properties and tell you exactly what they mean. A lot of these properties you will see across all tasks as well as the package because of everything's base structure The Container. BypassPrepare Should the statement be prepared before sending to the connection manager destination (True/False) Connection This is simply the name of the connection manager that the task will use. We can get this from the connection manager tray at the bottom of the package. DelayValidation Really interesting property and it tells the task to not validate until it actually executes. A usage for this may be that you are operating on table yet to be created but at runtime you know the table will be there. Description Very simply the description of your Task. Disable Should the task be enabled or not? You can also set this through a context menu by right clicking on the task itself. DisableEventHandlers As a result of events that happen in the task, should the event handlers for the container fire? ExecValueVariable The variable assigned here will get or set the execution value of the task. Expressions Expressions as we mentioned earlier are a really powerful tool in SSIS and this graphic below shows us a small peek of what you can do. We select a property on the left and assign an expression to the value of that property on the right causing the value to be dynamically changed at runtime. One of the most obvious uses of this is that the property value can be built dynamically from within the package allowing you a great deal of flexibility FailPackageOnFailure If this task fails does the package? FailParentOnFailure If this task fails does the parent container? A task can he hosted inside another container i.e. the For Each Loop Container and this would then be the parent. ForcedExecutionValue This property allows you to hard code an execution value for the task. ForcedExecutionValueType What is the datatype of the ForcedExecutionValue? ForceExecutionResult Force the task to return a certain execution result. This could then be used by the workflow constraints. Possible values are None, Success, Failure and Completion. ForceExecutionValue Should we force the execution result? IsolationLevel This is the transaction isolation level of the task. IsStoredProcedure Certain optimisations are made by the task if it knows that the query is a Stored Procedure invocation. The docs say this will always be false unless the connection is an ADO connection. LocaleID Gets or sets the LocaleID of the container. LoggingMode Should we log for this container and what settings should we use? The value choices are UseParentSetting, Enabled and Disabled. MaximumErrorCount How many times can the task fail before we call it a day? Name Very simply the name of the task. ResultSetType How do you want the results of your query returned? The choices are ResultSetType_None, ResultSetType_SingleRow, ResultSetType_Rowset and ResultSetType_XML. SqlStatementSource Your Query/SQL Statement. SqlStatementSourceType The method of specifying the query. Your choices here are DirectInput, FileConnection and Variables TimeOut How long should the task wait to receive results? TransactionOption How should the task handle being asked to join a transaction? Usage Examples As we move through the examples we will only cover in them what we think you must know and what we think you should see. This means that some of the more elementary steps like setting up variables will be covered in the early examples but skipped and simply referred to in later ones. All these examples used the AventureWorks database that comes with SQL Server 2005. Returning a Single Value, Passing in Two Input Parameters So the first thing we are going to do is add some variables to our package. The graphic below shows us those variables having been defined. Here the CountOfEmployees variable will be used as the output from the query and EndDate and StartDate will be used as input parameters. As you can see all these variables have been scoped to the package. Scoping allows us to have domains for variables. Each container has a scope and remember a package is a container as well. Variable values of the parent container can be seen in child containers but cannot be passed back up to the parent from a child. Our following graphic has had a number of changes made. The first of those changes is that we have created and assigned an OLEDB connection manager to this Task ExecuteSQL Task Connection. The next thing is we have made sure that the SQLSourceType property is set to Direct Input as we will be writing in our statement ourselves. We have also specified that only a single row will be returned from this query. The expressions we typed in was: SELECT COUNT(*) AS CountOfEmployees FROM HumanResources.Employee WHERE (HireDate BETWEEN ? AND ?) Moving on now to the Parameter Mapping tab this is where we are going to tell the task about our input paramaters. We Add them to the window specifying their direction and datatype. A quick word here about the structure of the variable name. As you can see SSIS has preceeded the variable with the word user. This is a default namespace for variables but you can create your own. When defining your variables if you look at the variables window title bar you will see some icons. If you hover over the last one on the right you will see it says "Choose Variable Columns". If you click the button you will see a list of checkbox options and one of them is namespace. after checking this you will see now where you can define your own namespace. The next tab, result set, is where we need to get back the value(s) returned from our statement and assign to a variable which in our case is CountOfEmployees so we can use it later perhaps. Because we are only returning a single value then if you remember from earlier we are allowed to assign a name to the resultset but it must be the name of the column (or alias) from the query. A really cool feature of Business Intelligence Studio being hosted by Visual Studio is that we get breakpoint support for free. In our package we set a Breakpoint so we can break the package and have a look in a watch window at the variable values as they appear to our task and what the variable value of our resultset is after the task has done the assignment. Here's that window now. As you can see the count of employess that matched the data range was 2. Returning a Rowset In this example we are going to return a resultset back to a variable after the task has executed not just a single row single value. There are no input parameters required so the variables window is nice and straight forward. One variable of type object. Here is the statement that will form the soure for our Resultset. select p.ProductNumber, p.name, pc.Name as ProductCategoryNameFROM Production.ProductCategory pcJOIN Production.ProductSubCategory pscON pc.ProductCategoryID = psc.ProductCategoryIDJOIN Production.Product pON psc.ProductSubCategoryID = p.ProductSubCategoryID We need to make sure that we have selected Full result set as the ResultSet as shown below on the task's General tab. Because there are no input parameters we can skip the parameter mapping tab and move straight to the Result Set tab. Here we need to Add our variable defined earlier and map it to the result name of 0 (remember we covered this earlier) Once we run the task we can again set a breakpoint and have a look at the values coming back from the task. In the following graphic you can see the result set returned to us as a COM object. We can do some pretty interesting things with this COM object and in later articles that is exactly what we shall be doing. Return Values, Input/Output Parameters and Returning a Rowset from a Stored Procedure This example is pretty much going to give us a taste of everything. We have already covered in the previous example how to specify the ResultSet to be a Full result set so we will not cover it again here. For this example we are going to need 4 variables. One for the return value, one for the input parameter, one for the output parameter and one for the result set. Here is the statement we want to execute. Note how much cleaner it is than if you wanted to do it using the current version of DTS. In the Parameter Mapping tab we are going to Add our variables and specify their direction and datatypes. In the Result Set tab we can now map our final variable to the rowset returned from the stored procedure. It really is as simple as that and we were amazed at how much easier it is than in DTS 2000. Passing in the SQL Statement from a Variable SSIS as we have mentioned is hugely more flexible than its predecessor and one of the things you will notice when moving around the tasks and the adapters is that a lot of them accept a variable as an input for something they need. The ExecuteSQL task is no different. It will allow us to pass in a string variable as the SQL Statement. This variable value could have been set earlier on from inside the package or it could have been populated from outside using a configuration. The ResultSet property is set to single row and we'll show you why in a second when we look at the variables. Note also the SQLSourceType property. Here's the General Tab again. Looking at the variable we have in this package you can see we have only two. One for the return value from the statement and one which is obviously for the statement itself. Again we need to map the Result name to our variable and this can be a named Result Name (The column name or alias returned by the query) and not 0. The expected result into our variable should be the amount of rows in the Person.Contact table and if we look in the watch window we see that it is.   Passing in the SQL Statement from a File The final example we are going to show is a really interesting one. We are going to pass in the SQL statement to the task by using a file connection manager. The file itself contains the statement to run. The first thing we are going to need to do is create our file connection mananger to point to our file. Click in the connections tray at the bottom of the designer, right click and choose "New File Connection" As you can see in the graphic below we have chosen to use an existing file and have passed in the name as well. Have a look around at the other "Usage Type" values available whilst you are here. Having set that up we can now see in the connection manager tray our file connection manager sitting alongside our OLE-DB connection we have been using for the rest of these examples. Now we can go back to the familiar General Tab to set up how the task will accept our file connection as the source. All the other properties in this task are set up exactly as we have been doing for other examples depending on the options chosen so we will not cover them again here.   We hope you will agree that the Execute SQL Task has changed considerably in this release from its DTS predecessor. It has a lot of options available but once you have configured it a few times you get to learn what needs to go where. We hope you have found this article useful.

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  • AngularJs ng-cloak Problems on large Pages

    - by Rick Strahl
    I’ve been working on a rather complex and large Angular page. Unlike a typical AngularJs SPA style ‘application’ this particular page is just that: a single page with a large amount of data on it that has to be visible all at once. The problem is that when this large page loads it flickers and displays template markup briefly before kicking into its actual content rendering. This is is what the Angular ng-cloak is supposed to address, but in this case I had no luck getting it to work properly. This application is a shop floor app where workers need to see all related information in one big screen view, so some of the benefits of Angular’s routing and view swapping features couldn’t be applied. Instead, we decided to have one very big view but lots of ng-controllers and directives to break out the logic for code separation. For code separation this works great – there are a number of small controllers that deal with their own individual and isolated application concerns. For HTML separation we used partial ASP.NET MVC Razor Views which made breaking out the HTML into manageable pieces super easy and made migration of this page from a previous server side Razor page much easier. We were also able to leverage most of our server side localization without a lot of  changes as a bonus. But as a result of this choice the initial HTML document that loads is rather large – even without any data loaded into it, resulting in a fairly large DOM tree that Angular must manage. Large Page and Angular Startup The problem on this particular page is that there’s quite a bit of markup – 35k’s worth of markup without any data loaded, in fact. It’s a large HTML page with a complex DOM tree. There are quite a lot of Angular {{ }} markup expressions in the document. Angular provides the ng-cloak directive to try and hide the element it cloaks so that you don’t see the flash of these markup expressions when the page initially loads before Angular has a chance to render the data into the markup expressions.<div id="mainContainer" class="mainContainer boxshadow" ng-app="app" ng-cloak> Note the ng-cloak attribute on this element, which here is an outer wrapper element of the most of this large page’s content. ng-cloak is supposed to prevent displaying the content below it, until Angular has taken control and is ready to render the data into the templates. Alas, with this large page the end result unfortunately is a brief flicker of un-rendered markup which looks like this: It’s brief, but plenty ugly – right?  And depending on the speed of the machine this flash gets more noticeable with slow machines that take longer to process the initial HTML DOM. ng-cloak Styles ng-cloak works by temporarily hiding the marked up element and it does this by essentially applying a style that does this:[ng\:cloak], [ng-cloak], [data-ng-cloak], [x-ng-cloak], .ng-cloak, .x-ng-cloak { display: none !important; } This style is inlined as part of AngularJs itself. If you looking at the angular.js source file you’ll find this at the very end of the file:!angular.$$csp() && angular.element(document) .find('head') .prepend('<style type="text/css">@charset "UTF-8";[ng\\:cloak],[ng-cloak],' + '[data-ng-cloak],[x-ng-cloak],.ng-cloak,.x-ng-cloak,' + '.ng-hide{display:none !important;}ng\\:form{display:block;}' '.ng-animate-block-transitions{transition:0s all!important;-webkit-transition:0s all!important;}' + '</style>'); This is is meant to initially hide any elements that contain the ng-cloak attribute or one of the other Angular directive permutation markup. Unfortunately on this particular web page ng-cloak had no effect – I still see the flicker. Why doesn’t ng-cloak work? The problem is of course – timing. The problem is that Angular actually needs to get control of the page before it ever starts doing anything like process even the ng-cloak attribute (or style etc). Because this page is rather large (about 35k of non-data HTML) it takes a while for the DOM to actually plow through the HTML. With the Angular <script> tag defined at the bottom of the page after the HTML DOM content there’s a slight delay which causes the flicker. For smaller pages the initial DOM load/parse cycle is so fast that the markup never shows, but with larger content pages it may show and become an annoying problem. Workarounds There a number of simple ways around this issue and some of them are hinted on in the Angular documentation. Load Angular Sooner One obvious thing that would help with this is to load Angular at the top of the page  BEFORE the DOM loads and that would give it much earlier control. The old ng-cloak documentation actually recommended putting the Angular.js script into the header of the page (apparently this was recently removed), but generally it’s not a good practice to load scripts in the header for page load performance. This is especially true if you load other libraries like jQuery which should be loaded prior to loading Angular so it can use jQuery rather than its own jqLite subset. This is not something I normally would like to do and also something that I’d likely forget in the future and end up right back here :-). Use ng-include for Child Content Angular supports nesting of child templates via the ng-include directive which essentially delay loads HTML content. This helps by removing a lot of the template content out of the main page and so getting control to Angular a lot sooner in order to hide the markup template content. In the application in question, I realize that in hindsight it might have been smarter to break this page out with client side ng-include directives instead of MVC Razor partial views we used to break up the page sections. Razor partial views give that nice separation as well, but in the end Razor puts humpty dumpty (ie. the HTML) back together into a whole single and rather large HTML document. Razor provides the logical separation, but still results in a large physical result document. But Razor also ended up being helpful to have a few security related blocks handled via server side template logic that simply excludes certain parts of the UI the user is not allowed to see – something that you can’t really do with client side exclusion like ng-hide/ng-show – client side content is always there whereas on the server side you can simply not send it to the client. Another reason I’m not a huge fan of ng-include is that it adds another HTTP hit to a request as templates are loaded from the server dynamically as needed. Given that this page was already heavy with resources adding another 10 separate ng-include directives wouldn’t be beneficial :-) ng-include is a valid option if you start from scratch and partition your logic. Of course if you don’t have complex pages, having completely separate views that are swapped in as they are accessed are even better, but we didn’t have this option due to the information having to be on screen all at once. Avoid using {{ }}  Expressions The biggest issue that ng-cloak attempts to address isn’t so much displaying the original content – it’s displaying empty {{ }} markup expression tags that get embedded into content. It gives you the dreaded “now you see it, now you don’t” effect where you sometimes see three separate rendering states: Markup junk, empty views, then views filled with data. If we can remove {{ }} expressions from the page you remove most of the perceived double draw effect as you would effectively start with a blank form and go straight to a filled form. To do this you can forego {{ }}  expressions and replace them with ng-bind directives on DOM elements. For example you can turn:<div class="list-item-name listViewOrderNo"> <a href='#'>{{lineItem.MpsOrderNo}}</a> </div>into:<div class="list-item-name listViewOrderNo"> <a href="#" ng-bind="lineItem.MpsOrderNo"></a> </div> to get identical results but because the {{ }}  expression has been removed there’s no double draw effect for this element. Again, not a great solution. The {{ }} syntax sure reads cleaner and is more fluent to type IMHO. In some cases you may also not have an outer element to attach ng-bind to which then requires you to artificially inject DOM elements into the page. This is especially painful if you have several consecutive values like {{Firstname}} {{Lastname}} for example. It’s an option though especially if you think of this issue up front and you don’t have a ton of expressions to deal with. Add the ng-cloak Styles manually You can also explicitly define the .css styles that Angular injects via code manually in your application’s style sheet. By doing so the styles become immediately available and so are applied right when the page loads – no flicker. I use the minimal:[ng-cloak] { display: none !important; } which works for:<div id="mainContainer" class="mainContainer dialog boxshadow" ng-app="app" ng-cloak> If you use one of the other combinations add the other CSS selectors as well or use the full style shown earlier. Angular will still load its version of the ng-cloak styling but it overrides those settings later, but this will do the trick of hiding the content before that CSS is injected into the page. Adding the CSS in your own style sheet works well, and is IMHO by far the best option. The nuclear option: Hiding the Content manually Using the explicit CSS is the best choice, so the following shouldn’t ever be necessary. But I’ll mention it here as it gives some insight how you can hide/show content manually on load for other frameworks or in your own markup based templates. Before I figured out that I could explicitly embed the CSS style into the page, I had tried to figure out why ng-cloak wasn’t doing its job. After wasting an hour getting nowhere I finally decided to just manually hide and show the container. The idea is simple – initially hide the container, then show it once Angular has done its initial processing and removal of the template markup from the page. You can manually hide the content and make it visible after Angular has gotten control. To do this I used:<div id="mainContainer" class="mainContainer boxshadow" ng-app="app" style="display:none"> Notice the display: none style that explicitly hides the element initially on the page. Then once Angular has run its initialization and effectively processed the template markup on the page you can show the content. For Angular this ‘ready’ event is the app.run() function:app.run( function ($rootScope, $location, cellService) { $("#mainContainer").show(); … }); This effectively removes the display:none style and the content displays. By the time app.run() fires the DOM is ready to displayed with filled data or at least empty data – Angular has gotten control. Edge Case Clearly this is an edge case. In general the initial HTML pages tend to be reasonably sized and the load time for the HTML and Angular are fast enough that there’s no flicker between the rendering times. This only becomes an issue as the initial pages get rather large. Regardless – if you have an Angular application it’s probably a good idea to add the CSS style into your application’s CSS (or a common shared one) just to make sure that content is always hidden. You never know how slow of a browser somebody might be running and while your super fast dev machine might not show any flicker, grandma’s old XP box very well might…© Rick Strahl, West Wind Technologies, 2005-2014Posted in Angular  JavaScript  CSS  HTML   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Using the Data Form Web Part (SharePoint 2010) Site Agnostically!

    - by David Jacobus
    Originally posted on: http://geekswithblogs.net/djacobus/archive/2013/10/24/154465.aspxAs a Developer whom has worked closely with web designers (Power users) in a SharePoint environment, I have come across the issue of making the Data Form Web Part reusable across the site collection! In SharePoint 2007 it was very easy and this blog pointed the way to make it happen: Josh Gaffey's Blog. In SharePoint 2010 something changed! This method failed except for using a Data Form Web Part that pointed to a list in the Site Collection Root! I am making this discussion relative to a developer whom creates a solution (WSP) with all the artifacts embedded and the user shouldn’t have any involvement in the process except to activate features. The Scenario: 1. A Power User creates a Data Form Web Part using SharePoint Designer 2010! It is a great web part the uses all the power of SharePoint Designer and XSLT (Conditional formatting, etc.). 2. Other Users in the site collection want to use that specific web part in sub sites in the site collection. Pointing to a list with the same name, not at the site collection root! The Issues: 1. The Data Form Web Part Data Source uses a List ID (GUID) to point to the specific list. Which means a list in a sub site will have a list with a new GUID different than the one which was created with SharePoint Designer! Obviously, the List needs to be the same List (Fields, Content Types, etc.) with different data. 2. How can we make this web part site agnostic, and dependent only on the lists Name? I had this problem come up over and over and decided to put my solution forward! The Solution: 1. Use the XSL of the Data Form Web Part Created By the Power User in SharePoint Designer! 2. Extend the OOTB Data Form Web Part to use this XSL and Point to a List by name. The solution points to a hybrid solution that requires some coding (Developer) and the XSL (Power User) artifacts put together in a Visual Studio SharePoint Solution. Here are the solution steps in summary: 1. Create an empty SharePoint project in Visual Studio 2. Create a Module and Feature and put the XSL file created by the Power User into it a. Scope the feature to web 3. Create a Feature Receiver to Create the List. The same list from which the Data Form Web Part was created with by the Power User. a. Scope the feature to web 4. Create a Web Part extending the Data Form Web a. Point the Data Form Web Part to point to the List by Name b. Point the Data Form Web Part XSL link to the XSL added using the Module feature c. Scope The feature to Site i. This is because all web parts are in the site collection web part gallery. So in a Narrative Summary: We are creating a list in code which has the same name and (site Columns) as the list from which the Power User created the Data Form Web Part Using SharePoint Designer. We are creating a Web Part in code which extends the OOTB Data Form Web Part to point to a list by name and use the XSL created by the Power User. Okay! Here are the steps with images and code! At the end of this post I will provide a link to the code for a solution which works in any site! I want to TOOT the HORN for the power of this solution! It is the mantra a use with all my clients! What is a basic skill a SharePoint Developer: Create an application that uses the data from a SharePoint list and make that data visible to the user in a manner which meets requirements! Create an Empty SharePoint 2010 Project Here I am naming my Project DJ.DataFormWebPart Create a Code Folder Copy and paste the Extension and Utilities classes (Found in the solution provided at the end of this post) Change the Namespace to match this project The List to which the Data Form Web Part which was used to make the XSL by the Power User in SharePoint Designer is now going to be created in code! If already in code, then all the better! Here I am going to create a list in the site collection root and add some data to it! For the purpose of this discussion I will actually create this list in code before using SharePoint Designer for simplicity! So here I create the List and deploy it within this solution before I do anything else. I will use a List I created before for demo purposes. Footer List is used within the footer of my master page. Add a new Feature: Here I name the Feature FooterList and add a Feature Event Receiver: Here is the code for the Event Receiver: I have a previous blog post about adding lists in code so I will not take time to narrate this code: using System; using System.Runtime.InteropServices; using System.Security.Permissions; using Microsoft.SharePoint; using DJ.DataFormWebPart.Code; namespace DJ.DataFormWebPart.Features.FooterList { /// <summary> /// This class handles events raised during feature activation, deactivation, installation, uninstallation, and upgrade. /// </summary> /// <remarks> /// The GUID attached to this class may be used during packaging and should not be modified. /// </remarks> [Guid("a58644fd-9209-41f4-aa16-67a53af7a9bf")] public class FooterListEventReceiver : SPFeatureReceiver { SPWeb currentWeb = null; SPSite currentSite = null; const string columnGroup = "DJ"; const string ctName = "FooterContentType"; // Uncomment the method below to handle the event raised after a feature has been activated. public override void FeatureActivated(SPFeatureReceiverProperties properties) { using (SPWeb spWeb = properties.GetWeb() as SPWeb) { using (SPSite site = new SPSite(spWeb.Site.ID)) { using (SPWeb rootWeb = site.OpenWeb(site.RootWeb.ID)) { //add the fields addFields(rootWeb); //add content type SPContentType testCT = rootWeb.ContentTypes[ctName]; // we will not create the content type if it exists if (testCT == null) { //the content type does not exist add it addContentType(rootWeb, ctName); } if ((spWeb.Lists.TryGetList("FooterList") == null)) { //create the list if it dosen't to exist CreateFooterList(spWeb, site); } } } } } #region ContentType public void addFields(SPWeb spWeb) { Utilities.addField(spWeb, "Link", SPFieldType.URL, false, columnGroup); Utilities.addField(spWeb, "Information", SPFieldType.Text, false, columnGroup); } private static void addContentType(SPWeb spWeb, string name) { SPContentType myContentType = new SPContentType(spWeb.ContentTypes["Item"], spWeb.ContentTypes, name) { Group = columnGroup }; spWeb.ContentTypes.Add(myContentType); addContentTypeLinkages(spWeb, myContentType); myContentType.Update(); } public static void addContentTypeLinkages(SPWeb spWeb, SPContentType ct) { Utilities.addContentTypeLink(spWeb, "Link", ct); Utilities.addContentTypeLink(spWeb, "Information", ct); } private void CreateFooterList(SPWeb web, SPSite site) { Guid newListGuid = web.Lists.Add("FooterList", "Footer List", SPListTemplateType.GenericList); SPList newList = web.Lists[newListGuid]; newList.ContentTypesEnabled = true; var footer = site.RootWeb.ContentTypes[ctName]; newList.ContentTypes.Add(footer); newList.ContentTypes.Delete(newList.ContentTypes["Item"].Id); newList.Update(); var view = newList.DefaultView; //add all view fields here //view.ViewFields.Add("NewsTitle"); view.ViewFields.Add("Link"); view.ViewFields.Add("Information"); view.Update(); } } } Basically created a content type with two site columns Link and Information. I had to change some code as we are working at the SPWeb level and need Content Types at the SPSite level! I’ll use a new Site Collection for this demo (Best Practice) keep old artifacts from impinging on development: Next we will add this list to the root of the site collection by deploying this solution, add some data and then use SharePoint Designer to create a Data Form Web Part. The list has been added, now let’s add some data: Okay let’s add a Data Form Web Part in SharePoint Designer. Create a new web part page in the site pages library: I will name it TestWP.aspx and edit it in advanced mode: Let’s add an empty Data Form Web Part to the web part zone: Click on the web part to add a data source: Choose FooterList in the Data Source menu: Choose appropriate fields and select insert as multiple item view: Here is what it look like after insertion: Let’s add some conditional formatting if the information filed is not blank: Choose Create (right side) apply formatting: Choose the Information Field and set the condition not null: Click Set Style: Here is the result: Okay! Not flashy but simple enough for this demo. Remember this is the job of the Power user! All we want from this web part is the XLS-Style Sheet out of SharePoint Designer. We are going to use it as the XSL for our web part which we will be creating next. Let’s add a web part to our project extending the OOTB Data Form Web Part. Add new item from the Visual Studio add menu: Choose Web Part: Change WebPart to DataFormWebPart (Oh well my namespace needs some improvement, but it will sure make it readily identifiable as an extended web part!) Below is the code for this web part: using System; using System.ComponentModel; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using Microsoft.SharePoint; using Microsoft.SharePoint.WebControls; using System.Text; namespace DJ.DataFormWebPart.DataFormWebPart { [ToolboxItemAttribute(false)] public class DataFormWebPart : Microsoft.SharePoint.WebPartPages.DataFormWebPart { protected override void OnInit(EventArgs e) { base.OnInit(e); this.ChromeType = PartChromeType.None; this.Title = "FooterListDF"; try { //SPSite site = SPContext.Current.Site; SPWeb web = SPContext.Current.Web; SPList list = web.Lists.TryGetList("FooterList"); if (list != null) { string queryList1 = "<Query><Where><IsNotNull><FieldRef Name='Title' /></IsNotNull></Where><OrderBy><FieldRef Name='Title' Ascending='True' /></OrderBy></Query>"; uint maximumRowList1 = 10; SPDataSource dataSourceList1 = GetDataSource(list.Title, web.Url, list, queryList1, maximumRowList1); this.DataSources.Add(dataSourceList1); this.XslLink = web.Url + "/Assests/Footer.xsl"; this.ParameterBindings = BuildDataFormParameters(); this.DataBind(); } } catch (Exception ex) { this.Controls.Add(new LiteralControl("ERROR: " + ex.Message)); } } private SPDataSource GetDataSource(string dataSourceId, string webUrl, SPList list, string query, uint maximumRow) { SPDataSource dataSource = new SPDataSource(); dataSource.UseInternalName = true; dataSource.ID = dataSourceId; dataSource.DataSourceMode = SPDataSourceMode.List; dataSource.List = list; dataSource.SelectCommand = "" + query + ""; Parameter listIdParam = new Parameter("ListID"); listIdParam.DefaultValue = list.ID.ToString( "B").ToUpper(); Parameter maximumRowsParam = new Parameter("MaximumRows"); maximumRowsParam.DefaultValue = maximumRow.ToString(); QueryStringParameter rootFolderParam = new QueryStringParameter("RootFolder", "RootFolder"); dataSource.SelectParameters.Add(listIdParam); dataSource.SelectParameters.Add(maximumRowsParam); dataSource.SelectParameters.Add(rootFolderParam); dataSource.UpdateParameters.Add(listIdParam); dataSource.DeleteParameters.Add(listIdParam); dataSource.InsertParameters.Add(listIdParam); return dataSource; } private string BuildDataFormParameters() { StringBuilder parameters = new StringBuilder("<ParameterBindings><ParameterBinding Name=\"dvt_apos\" Location=\"Postback;Connection\"/><ParameterBinding Name=\"UserID\" Location=\"CAMLVariable\" DefaultValue=\"CurrentUserName\"/><ParameterBinding Name=\"Today\" Location=\"CAMLVariable\" DefaultValue=\"CurrentDate\"/>"); parameters.Append("<ParameterBinding Name=\"dvt_firstrow\" Location=\"Postback;Connection\"/>"); parameters.Append("<ParameterBinding Name=\"dvt_nextpagedata\" Location=\"Postback;Connection\"/>"); parameters.Append("<ParameterBinding Name=\"dvt_adhocmode\" Location=\"Postback;Connection\"/>"); parameters.Append("<ParameterBinding Name=\"dvt_adhocfiltermode\" Location=\"Postback;Connection\"/>"); parameters.Append("</ParameterBindings>"); return parameters.ToString(); } } } The OnInit method we use to set the list name and the XSL Link property of the Data Form Web Part. We do not have the link to XSL in our Solution so we will add the XSL now: Add a Module in the Visual Studio add menu: Rename Sample.txt in the module to footer.xsl and then copy the XSL from SharePoint Designer Look at elements.xml to where the footer.xsl is being provisioned to which is Assets/footer.xsl, make sure the Web parts xsl link is pointing to this url: Okay we are good to go! Let’s check our features and package: DataFormWebPart should be scoped to site and have the web part: The Footer List feature should be scoped to web and have the Assets module (Okay, I see, a spelling issue but it won’t affect this demo) If everything is correct we should be able to click a couple of sub site feature activations and have our list and web part in a sub site. (In fact this solution can be activated anywhere) Here is the list created at SubSite1 with new data It. Next let’s add the web part on a test page and see if it works as expected: It does! So we now have a repeatable way to use a WSP to move a Data Form Web Part around our sites! Here is a link to the code: DataFormWebPart Solution

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  • Partitioned Repository for WebCenter Content using Oracle Database 11g

    - by Adao Junior
    One of the biggest challenges for content management solutions is related to the storage management due the high volumes of the unstoppable growing of information. Even if you have storage appliances and a lot of terabytes, thinks like backup, compression, deduplication, storage relocation, encryption, availability could be a nightmare. One standard option that you have with the Oracle WebCenter Content is to store data to the database. And the Oracle Database allows you leverage features like compression, deduplication, encryption and seamless backup. But with a huge volume, the challenge is passed to the DBA to keep the WebCenter Content Database up and running. One solution is the use of DB partitions for your content repository, but what are the implications of this? Can I fit this with my business requirements? Well, yes. It’s up to you how you will manage that, you just need a good plan. During you “storage brainstorm plan” take in your mind what you need, such as storage petabytes of documents? You need everything on-line? There’s a way to logically separate the “good content” from the “legacy content”? The first thing that comes to my mind is to use the creation date of the document, but you need to remember that this document could receive a lot of revisions and maybe you can consider the revision creation date. Your plan can have also complex rules like per Document Type or per a custom metadata like department or an hybrid per date, per DocType and an specific virtual folder. Extrapolation the use, you can have your repository distributed in different servers, different disks, different disk types (Such as ssds, sas, sata, tape,…), separated accordingly your business requirements, separating the “hot” content from the legacy and easily matching your compliance requirements. If you think to use by revision, the simple way is to consider the dId, that is the sequential unique id for every content created using the WebCenter Content or the dLastModified that is the date field of the FileStorage table that contains the date of inclusion of the content to the DB Table using SecureFiles. Using the scenario of partitioned repository using an hierarchical separation by date, we will transform the FileStorage table in an partitioned table using  “Partition by Range” of the dLastModified column (You can use the dId or a join with other tables for other metadata such as dDocType, Security, etc…). The test scenario bellow covers: Previous existent data on the JDBC Storage to be migrated to the new partitioned JDBC Storage Partition by Date Automatically generation of new partitions based on a pre-defined interval (Available only with Oracle Database 11g+) Deduplication and Compression for legacy data Oracle WebCenter Content 11g PS5 (Could present some customizations that do not affect the test scenario) For the test case you need some data stored using JDBC Storage to be the “legacy” data. If you do not have done before, just create an Storage rule pointed to the JDBC Storage: Enable the metadata StorageRule in the UI and upload some documents using this rule. For this test case you can run using the schema owner or an dba user. We will use the schema owner TESTS_OCS. I can’t forgot to tell that this is just a test and you should do a proper backup of your environment. When you use the schema owner, you need some privileges, using the dba user grant the privileges needed: REM Grant privileges required for online redefinition. GRANT EXECUTE ON DBMS_REDEFINITION TO TESTS_OCS; GRANT ALTER ANY TABLE TO TESTS_OCS; GRANT DROP ANY TABLE TO TESTS_OCS; GRANT LOCK ANY TABLE TO TESTS_OCS; GRANT CREATE ANY TABLE TO TESTS_OCS; GRANT SELECT ANY TABLE TO TESTS_OCS; REM Privileges required to perform cloning of dependent objects. GRANT CREATE ANY TRIGGER TO TESTS_OCS; GRANT CREATE ANY INDEX TO TESTS_OCS; In our test scenario we will separate the content as Legacy, Day1, Day2, Day3 and Future. This last one will partitioned automatically using 3 tablespaces in a round robin mode. In a real scenario the partition rule could be per month, per year or any rule that you choose. Table spaces for the test scenario: CREATE TABLESPACE TESTS_OCS_PART_LEGACY DATAFILE 'tests_ocs_part_legacy.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY1 DATAFILE 'tests_ocs_part_day1.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY2 DATAFILE 'tests_ocs_part_day2.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_DAY3 DATAFILE 'tests_ocs_part_day3.dat' SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_A 'tests_ocs_part_round_robin_a.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_B 'tests_ocs_part_round_robin_b.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; CREATE TABLESPACE TESTS_OCS_PART_ROUND_ROBIN_C 'tests_ocs_part_round_robin_c.dat' DATAFILE SIZE 500K AUTOEXTEND ON NEXT 500K MAXSIZE UNLIMITED; Before start, gather optimizer statistics on the actual FileStorage table: EXEC DBMS_STATS.GATHER_TABLE_STATS(USER, 'FileStorage', cascade => TRUE); Now check if is possible execute the redefinition process: EXEC DBMS_REDEFINITION.CAN_REDEF_TABLE('TESTS_OCS', 'FileStorage',DBMS_REDEFINITION.CONS_USE_PK); If no errors messages, you are good to go. Create a Partitioned Interim FileStorage table. You need to create a new table with the partition information to act as an interim table: CREATE TABLE FILESTORAGE_Part ( DID NUMBER(*,0) NOT NULL ENABLE, DRENDITIONID VARCHAR2(30 CHAR) NOT NULL ENABLE, DLASTMODIFIED TIMESTAMP (6), DFILESIZE NUMBER(*,0), DISDELETED VARCHAR2(1 CHAR), BFILEDATA BLOB ) LOB (BFILEDATA) STORE AS SECUREFILE ( ENABLE STORAGE IN ROW NOCACHE LOGGING KEEP_DUPLICATES NOCOMPRESS ) PARTITION BY RANGE (DLASTMODIFIED) INTERVAL (NUMTODSINTERVAL(1,'DAY')) STORE IN (TESTS_OCS_PART_ROUND_ROBIN_A, TESTS_OCS_PART_ROUND_ROBIN_B, TESTS_OCS_PART_ROUND_ROBIN_C) ( PARTITION FILESTORAGE_PART_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_LEGACY LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_LEGACY RETENTION NONE DEDUPLICATE COMPRESS HIGH ), PARTITION FILESTORAGE_PART_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY1 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY1 RETENTION AUTO KEEP_DUPLICATES COMPRESS ), PARTITION FILESTORAGE_PART_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY2 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY2 RETENTION AUTO KEEP_DUPLICATES NOCOMPRESS ), PARTITION FILESTORAGE_PART_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) TABLESPACE TESTS_OCS_PART_DAY3 LOB (BFILEDATA) STORE AS SECUREFILE ( TABLESPACE TESTS_OCS_PART_DAY3 RETENTION AUTO KEEP_DUPLICATES NOCOMPRESS ) ); After the creation you should see your partitions defined. Note that only the fixed range partitions have been created, none of the interval partition have been created. Start the redefinition process: BEGIN DBMS_REDEFINITION.START_REDEF_TABLE( uname => 'TESTS_OCS' ,orig_table => 'FileStorage' ,int_table => 'FileStorage_PART' ,col_mapping => NULL ,options_flag => DBMS_REDEFINITION.CONS_USE_PK ); END; This operation can take some time to complete, depending how many contents that you have and on the size of the table. Using the DBA user you can check the progress with this command: SELECT * FROM v$sesstat WHERE sid = 1; Copy dependent objects: DECLARE redefinition_errors PLS_INTEGER := 0; BEGIN DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS( uname => 'TESTS_OCS' ,orig_table => 'FileStorage' ,int_table => 'FileStorage_PART' ,copy_indexes => DBMS_REDEFINITION.CONS_ORIG_PARAMS ,copy_triggers => TRUE ,copy_constraints => TRUE ,copy_privileges => TRUE ,ignore_errors => TRUE ,num_errors => redefinition_errors ,copy_statistics => FALSE ,copy_mvlog => FALSE ); IF (redefinition_errors > 0) THEN DBMS_OUTPUT.PUT_LINE('>>> FileStorage to FileStorage_PART temp copy Errors: ' || TO_CHAR(redefinition_errors)); END IF; END; With the DBA user, verify that there's no errors: SELECT object_name, base_table_name, ddl_txt FROM DBA_REDEFINITION_ERRORS; *Note that will show 2 lines related to the constrains, this is expected. Synchronize the interim table FileStorage_PART: BEGIN DBMS_REDEFINITION.SYNC_INTERIM_TABLE( uname => 'TESTS_OCS', orig_table => 'FileStorage', int_table => 'FileStorage_PART'); END; Gather statistics on the new table: EXEC DBMS_STATS.GATHER_TABLE_STATS(USER, 'FileStorage_PART', cascade => TRUE); Complete the redefinition: BEGIN DBMS_REDEFINITION.FINISH_REDEF_TABLE( uname => 'TESTS_OCS', orig_table => 'FileStorage', int_table => 'FileStorage_PART'); END; During the execution the FileStorage table is locked in exclusive mode until finish the operation. After the last command the FileStorage table is partitioned. If you have contents out of the range partition, you should see the new partitions created automatically, not generating an error if you “forgot” to create all the future ranges. You will see something like: You now can drop the FileStorage_PART table: border-bottom-width: 1px; border-bottom-style: solid; text-align: left; border-left-color: silver; border-left-width: 1px; border-left-style: solid; padding-bottom: 4px; line-height: 12pt; background-color: #f4f4f4; margin-top: 20px; margin-right: 0px; margin-bottom: 10px; margin-left: 0px; padding-left: 4px; width: 97.5%; padding-right: 4px; font-family: 'Courier New', Courier, monospace; direction: ltr; max-height: 200px; font-size: 8pt; overflow-x: auto; overflow-y: auto; border-top-color: silver; border-top-width: 1px; border-top-style: solid; cursor: text; border-right-color: silver; border-right-width: 1px; border-right-style: solid; padding-top: 4px; " id="codeSnippetWrapper"> DROP TABLE FileStorage_PART PURGE; To check the FileStorage table is valid and is partitioned, use the command: SELECT num_rows,partitioned FROM user_tables WHERE table_name = 'FILESTORAGE'; You can list the contents of the FileStorage table in a specific partition, per example: SELECT * FROM FileStorage PARTITION (FILESTORAGE_PART_LEGACY) Some useful commands that you can use to check the partitions, note that you need to run using a DBA user: SELECT * FROM DBA_TAB_PARTITIONS WHERE table_name = 'FILESTORAGE';   SELECT * FROM DBA_TABLESPACES WHERE tablespace_name like 'TESTS_OCS%'; After the redefinition process complete you have a new FileStorage table storing all content that has the Storage rule pointed to the JDBC Storage and partitioned using the rule set during the creation of the temporary interim FileStorage_PART table. At this point you can test the WebCenter Content downloading the documents (Original and Renditions). Note that the content could be already in the cache area, take a look in the weblayout directory to see if a file with the same id is there, then click on the web rendition of your test file and see if have created the file and you can open, this means that is all working. The redefinition process can be repeated many times, this allow you test what the better layout, over and over again. Now some interesting maintenance actions related to the partitions: Make an tablespace read only. No issues viewing, the WebCenter Content do not alter the revisions When try to delete an content that is part of an read only tablespace, an error will occurs and the document will not be deleted The only way to prevent errors today is creating an custom component that checks the partitions and if you have an document in an “Read Only” repository, execute the deletion process of the metadata and mark the document to be deleted on the next db maintenance, like a new redefinition. Take an tablespace off-line for archiving purposes or any other reason. When you try open an document that is included in this tablespace will receive an error that was unable to retrieve the content, but the others online tablespaces are not affected. Same behavior when deleting documents. Again, an custom component is the solution. If you have an document “out of range”, the component can show an message that the repository for that document is offline. This can be extended to a option to the user to request to put online again. Moving some legacy content to an offline repository (table) using the Exchange option to move the content from one partition to a empty nonpartitioned table like FileStorage_LEGACY. Note that this option will remove the registers from the FileStorage and will not be able to open the stored content. You always need to keep in mind the indexes and constrains. An redefinition separating the original content (vault) from the renditions and separate by date ate the same time. This could be an option for DAM environments that want to have an special place for the renditions and put the original files in a storage with less performance. The process will be the same, you just need to change the script of the interim table to use composite partitioning. Will be something like: CREATE TABLE FILESTORAGE_RenditionPart ( DID NUMBER(*,0) NOT NULL ENABLE, DRENDITIONID VARCHAR2(30 CHAR) NOT NULL ENABLE, DLASTMODIFIED TIMESTAMP (6), DFILESIZE NUMBER(*,0), DISDELETED VARCHAR2(1 CHAR), BFILEDATA BLOB ) LOB (BFILEDATA) STORE AS SECUREFILE ( ENABLE STORAGE IN ROW NOCACHE LOGGING KEEP_DUPLICATES NOCOMPRESS ) PARTITION BY LIST (DRENDITIONID) SUBPARTITION BY RANGE (DLASTMODIFIED) ( PARTITION Vault VALUES ('primaryFile') ( SUBPARTITION FILESTORAGE_VAULT_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_VAULT_FUTURE VALUES LESS THAN (MAXVALUE) ) ,PARTITION WebLayout VALUES ('webViewableFile') ( SUBPARTITION FILESTORAGE_WEBLAYOUT_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_WEBLAYOUT_FUTURE VALUES LESS THAN (MAXVALUE) ) ,PARTITION Special VALUES ('Special') ( SUBPARTITION FILESTORAGE_SPECIAL_LEGACY VALUES LESS THAN (TO_DATE('05-APR-2012 12.00.00 AM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY1 VALUES LESS THAN (TO_DATE('06-APR-2012 07.25.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY2 VALUES LESS THAN (TO_DATE('06-APR-2012 07.55.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_DAY3 VALUES LESS THAN (TO_DATE('06-APR-2012 07.58.00 PM', 'DD-MON-YYYY HH.MI.SS AM')) LOB (BFILEDATA) STORE AS SECUREFILE , SUBPARTITION FILESTORAGE_SPECIAL_FUTURE VALUES LESS THAN (MAXVALUE) ) )ENABLE ROW MOVEMENT; The next post related to partitioned repository will come with an sample component to handle the possible exceptions when you need to take off line an tablespace/partition or move to another place. Also, we can include some integration to the Retention Management and Records Management. Another subject related to partitioning is the ability to create an FileStore Provider pointed to a different database, raising the level of the distributed storage vs. performance. Let us know if this is important to you or you have an use case not listed, leave a comment. Cross-posted on the blog.ContentrA.com

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  • Seeking on a Heap, and Two Useful DMVs

    - by Paul White
    So far in this mini-series on seeks and scans, we have seen that a simple ‘seek’ operation can be much more complex than it first appears.  A seek can contain one or more seek predicates – each of which can either identify at most one row in a unique index (a singleton lookup) or a range of values (a range scan).  When looking at a query plan, we will often need to look at the details of the seek operator in the Properties window to see how many operations it is performing, and what type of operation each one is.  As you saw in the first post in this series, the number of hidden seeking operations can have an appreciable impact on performance. Measuring Seeks and Scans I mentioned in my last post that there is no way to tell from a graphical query plan whether you are seeing a singleton lookup or a range scan.  You can work it out – if you happen to know that the index is defined as unique and the seek predicate is an equality comparison, but there’s no separate property that says ‘singleton lookup’ or ‘range scan’.  This is a shame, and if I had my way, the query plan would show different icons for range scans and singleton lookups – perhaps also indicating whether the operation was one or more of those operations underneath the covers. In light of all that, you might be wondering if there is another way to measure how many seeks of either type are occurring in your system, or for a particular query.  As is often the case, the answer is yes – we can use a couple of dynamic management views (DMVs): sys.dm_db_index_usage_stats and sys.dm_db_index_operational_stats. Index Usage Stats The index usage stats DMV contains counts of index operations from the perspective of the Query Executor (QE) – the SQL Server component that is responsible for executing the query plan.  It has three columns that are of particular interest to us: user_seeks – the number of times an Index Seek operator appears in an executed plan user_scans – the number of times a Table Scan or Index Scan operator appears in an executed plan user_lookups – the number of times an RID or Key Lookup operator appears in an executed plan An operator is counted once per execution (generating an estimated plan does not affect the totals), so an Index Seek that executes 10,000 times in a single plan execution adds 1 to the count of user seeks.  Even less intuitively, an operator is also counted once per execution even if it is not executed at all.  I will show you a demonstration of each of these things later in this post. Index Operational Stats The index operational stats DMV contains counts of index and table operations from the perspective of the Storage Engine (SE).  It contains a wealth of interesting information, but the two columns of interest to us right now are: range_scan_count – the number of range scans (including unrestricted full scans) on a heap or index structure singleton_lookup_count – the number of singleton lookups in a heap or index structure This DMV counts each SE operation, so 10,000 singleton lookups will add 10,000 to the singleton lookup count column, and a table scan that is executed 5 times will add 5 to the range scan count. The Test Rig To explore the behaviour of seeks and scans in detail, we will need to create a test environment.  The scripts presented here are best run on SQL Server 2008 Developer Edition, but the majority of the tests will work just fine on SQL Server 2005.  A couple of tests use partitioning, but these will be skipped if you are not running an Enterprise-equivalent SKU.  Ok, first up we need a database: USE master; GO IF DB_ID('ScansAndSeeks') IS NOT NULL DROP DATABASE ScansAndSeeks; GO CREATE DATABASE ScansAndSeeks; GO USE ScansAndSeeks; GO ALTER DATABASE ScansAndSeeks SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE ScansAndSeeks SET AUTO_CLOSE OFF, AUTO_SHRINK OFF, AUTO_CREATE_STATISTICS OFF, AUTO_UPDATE_STATISTICS OFF, PARAMETERIZATION SIMPLE, READ_COMMITTED_SNAPSHOT OFF, RESTRICTED_USER ; Notice that several database options are set in particular ways to ensure we get meaningful and reproducible results from the DMVs.  In particular, the options to auto-create and update statistics are disabled.  There are also three stored procedures, the first of which creates a test table (which may or may not be partitioned).  The table is pretty much the same one we used yesterday: The table has 100 rows, and both the key_col and data columns contain the same values – the integers from 1 to 100 inclusive.  The table is a heap, with a non-clustered primary key on key_col, and a non-clustered non-unique index on the data column.  The only reason I have used a heap here, rather than a clustered table, is so I can demonstrate a seek on a heap later on.  The table has an extra column (not shown because I am too lazy to update the diagram from yesterday) called padding – a CHAR(100) column that just contains 100 spaces in every row.  It’s just there to discourage SQL Server from choosing table scan over an index + RID lookup in one of the tests. The first stored procedure is called ResetTest: CREATE PROCEDURE dbo.ResetTest @Partitioned BIT = 'false' AS BEGIN SET NOCOUNT ON ; IF OBJECT_ID(N'dbo.Example', N'U') IS NOT NULL BEGIN DROP TABLE dbo.Example; END ; -- Test table is a heap -- Non-clustered primary key on 'key_col' CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ; IF @Partitioned = 'true' BEGIN -- Enterprise, Trial, or Developer -- required for partitioning tests IF SERVERPROPERTY('EngineEdition') = 3 BEGIN EXECUTE (' DROP TABLE dbo.Example ; IF EXISTS ( SELECT 1 FROM sys.partition_schemes WHERE name = N''PS'' ) DROP PARTITION SCHEME PS ; IF EXISTS ( SELECT 1 FROM sys.partition_functions WHERE name = N''PF'' ) DROP PARTITION FUNCTION PF ; CREATE PARTITION FUNCTION PF (INTEGER) AS RANGE RIGHT FOR VALUES (20, 40, 60, 80, 100) ; CREATE PARTITION SCHEME PS AS PARTITION PF ALL TO ([PRIMARY]) ; CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, padding CHAR(100) NOT NULL DEFAULT SPACE(100), CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ON PS (key_col); '); END ELSE BEGIN RAISERROR('Invalid SKU for partition test', 16, 1); RETURN; END; END ; -- Non-unique non-clustered index on the 'data' column CREATE NONCLUSTERED INDEX [IX dbo.Example data] ON dbo.Example (data) ; -- Add 100 rows INSERT dbo.Example WITH (TABLOCKX) ( key_col, data ) SELECT key_col = V.number, data = V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 100 ; END; GO The second stored procedure, ShowStats, displays information from the Index Usage Stats and Index Operational Stats DMVs: CREATE PROCEDURE dbo.ShowStats @Partitioned BIT = 'false' AS BEGIN -- Index Usage Stats DMV (QE) SELECT index_name = ISNULL(I.name, I.type_desc), scans = IUS.user_scans, seeks = IUS.user_seeks, lookups = IUS.user_lookups FROM sys.dm_db_index_usage_stats AS IUS JOIN sys.indexes AS I ON I.object_id = IUS.object_id AND I.index_id = IUS.index_id WHERE IUS.database_id = DB_ID(N'ScansAndSeeks') AND IUS.object_id = OBJECT_ID(N'dbo.Example', N'U') ORDER BY I.index_id ; -- Index Operational Stats DMV (SE) IF @Partitioned = 'true' SELECT index_name = ISNULL(I.name, I.type_desc), partitions = COUNT(IOS.partition_number), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; ELSE SELECT index_name = ISNULL(I.name, I.type_desc), range_scans = SUM(IOS.range_scan_count), single_lookups = SUM(IOS.singleton_lookup_count) FROM sys.dm_db_index_operational_stats ( DB_ID(N'ScansAndSeeks'), OBJECT_ID(N'dbo.Example', N'U'), NULL, NULL ) AS IOS JOIN sys.indexes AS I ON I.object_id = IOS.object_id AND I.index_id = IOS.index_id GROUP BY I.index_id, -- Key I.name, I.type_desc ORDER BY I.index_id; END; The final stored procedure, RunTest, executes a query written against the example table: CREATE PROCEDURE dbo.RunTest @SQL VARCHAR(8000), @Partitioned BIT = 'false' AS BEGIN -- No execution plan yet SET STATISTICS XML OFF ; -- Reset the test environment EXECUTE dbo.ResetTest @Partitioned ; -- Previous call will throw an error if a partitioned -- test was requested, but SKU does not support it IF @@ERROR = 0 BEGIN -- IO statistics and plan on SET STATISTICS XML, IO ON ; -- Test statement EXECUTE (@SQL) ; -- Plan and IO statistics off SET STATISTICS XML, IO OFF ; EXECUTE dbo.ShowStats @Partitioned; END; END; The Tests The first test is a simple scan of the heap table: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example'; The top result set comes from the Index Usage Stats DMV, so it is the Query Executor’s (QE) view.  The lower result is from Index Operational Stats, which shows statistics derived from the actions taken by the Storage Engine (SE).  We see that QE performed 1 scan operation on the heap, and SE performed a single range scan.  Let’s try a single-value equality seek on a unique index next: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 32'; This time we see a single seek on the non-clustered primary key from QE, and one singleton lookup on the same index by the SE.  Now for a single-value seek on the non-unique non-clustered index: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32'; QE shows a single seek on the non-clustered non-unique index, but SE shows a single range scan on that index – not the singleton lookup we saw in the previous test.  That makes sense because we know that only a single-value seek into a unique index is a singleton seek.  A single-value seek into a non-unique index might retrieve any number of rows, if you think about it.  The next query is equivalent to the IN list example seen in the first post in this series, but it is written using OR (just for variety, you understand): EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data = 32 OR data = 33'; The plan looks the same, and there’s no difference in the stats recorded by QE, but the SE shows two range scans.  Again, these are range scans because we are looking for two values in the data column, which is covered by a non-unique index.  I’ve added a snippet from the Properties window to show that the query plan does show two seek predicates, not just one.  Now let’s rewrite the query using BETWEEN: EXECUTE dbo.RunTest @SQL = 'SELECT data FROM Example WHERE data BETWEEN 32 AND 33'; Notice the seek operator only has one predicate now – it’s just a single range scan from 32 to 33 in the index – as the SE output shows.  For the next test, we will look up four values in the key_col column: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col IN (2,4,6,8)'; Just a single seek on the PK from the Query Executor, but four singleton lookups reported by the Storage Engine – and four seek predicates in the Properties window.  On to a more complex example: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WITH (INDEX([PK dbo.Example key_col])) WHERE key_col BETWEEN 1 AND 8'; This time we are forcing use of the non-clustered primary key to return eight rows.  The index is not covering for this query, so the query plan includes an RID lookup into the heap to fetch the data and padding columns.  The QE reports a seek on the PK and a lookup on the heap.  The SE reports a single range scan on the PK (to find key_col values between 1 and 8), and eight singleton lookups on the heap.  Remember that a bookmark lookup (RID or Key) is a seek to a single value in a ‘unique index’ – it finds a row in the heap or cluster from a unique RID or clustering key – so that’s why lookups are always singleton lookups, not range scans. Our next example shows what happens when a query plan operator is not executed at all: EXECUTE dbo.RunTest @SQL = 'SELECT key_col FROM Example WHERE key_col = 8 AND @@TRANCOUNT < 0'; The Filter has a start-up predicate which is always false (if your @@TRANCOUNT is less than zero, call CSS immediately).  The index seek is never executed, but QE still records a single seek against the PK because the operator appears once in an executed plan.  The SE output shows no activity at all.  This next example is 2008 and above only, I’m afraid: EXECUTE dbo.RunTest @SQL = 'SELECT * FROM Example WHERE key_col BETWEEN 1 AND 30', @Partitioned = 'true'; This is the first example to use a partitioned table.  QE reports a single seek on the heap (yes – a seek on a heap), and the SE reports two range scans on the heap.  SQL Server knows (from the partitioning definition) that it only needs to look at partitions 1 and 2 to find all the rows where key_col is between 1 and 30 – the engine seeks to find the two partitions, and performs a range scan seek on each partition. The final example for today is another seek on a heap – try to work out the output of the query before running it! EXECUTE dbo.RunTest @SQL = 'SELECT TOP (2) WITH TIES * FROM Example WHERE key_col BETWEEN 1 AND 50 ORDER BY $PARTITION.PF(key_col) DESC', @Partitioned = 'true'; Notice the lack of an explicit Sort operator in the query plan to enforce the ORDER BY clause, and the backward range scan. © 2011 Paul White email: [email protected] twitter: @SQL_Kiwi

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  • Testing Entity Framework applications, pt. 3: NDbUnit

    - by Thomas Weller
    This is the third of a three part series that deals with the issue of faking test data in the context of a legacy app that was built with Microsoft's Entity Framework (EF) on top of an MS SQL Server database – a scenario that can be found very often. Please read the first part for a description of the sample application, a discussion of some general aspects of unit testing in a database context, and of some more specific aspects of the here discussed EF/MSSQL combination. Lately, I wondered how you would ‘mock’ the data layer of a legacy application, when this data layer is made up of an MS Entity Framework (EF) model in combination with a MS SQL Server database. Originally, this question came up in the context of how you could enable higher-level integration tests (automated UI tests, to be exact) for a legacy application that uses this EF/MSSQL combo as its data store mechanism – a not so uncommon scenario. The question sparked my interest, and I decided to dive into it somewhat deeper. What I've found out is, in short, that it's not very easy and straightforward to do it – but it can be done. The two strategies that are best suited to fit the bill involve using either the (commercial) Typemock Isolator tool or the (free) NDbUnit framework. The use of Typemock was discussed in the previous post, this post now will present the NDbUnit approach... NDbUnit is an Apache 2.0-licensed open-source project, and like so many other Nxxx tools and frameworks, it is basically a C#/.NET port of the corresponding Java version (DbUnit namely). In short, it helps you in flexibly managing the state of a database in that it lets you easily perform basic operations (like e.g. Insert, Delete, Refresh, DeleteAll)  against your database and, most notably, lets you feed it with data from external xml files. Let's have a look at how things can be done with the help of this framework. Preparing the test data Compared to Typemock, using NDbUnit implies a totally different approach to meet our testing needs.  So the here described testing scenario requires an instance of an SQL Server database in operation, and it also means that the Entity Framework model that sits on top of this database is completely unaffected. First things first: For its interactions with the database, NDbUnit relies on a .NET Dataset xsd file. See Step 1 of their Quick Start Guide for a description of how to create one. With this prerequisite in place then, the test fixture's setup code could look something like this: [TestFixture, TestsOn(typeof(PersonRepository))] [Metadata("NDbUnit Quickstart URL",           "http://code.google.com/p/ndbunit/wiki/QuickStartGuide")] [Description("Uses the NDbUnit library to provide test data to a local database.")] public class PersonRepositoryFixture {     #region Constants     private const string XmlSchema = @"..\..\TestData\School.xsd";     #endregion // Constants     #region Fields     private SchoolEntities _schoolContext;     private PersonRepository _personRepository;     private INDbUnitTest _database;     #endregion // Fields     #region Setup/TearDown     [FixtureSetUp]     public void FixtureSetUp()     {         var connectionString = ConfigurationManager.ConnectionStrings["School_Test"].ConnectionString;         _database = new SqlDbUnitTest(connectionString);         _database.ReadXmlSchema(XmlSchema);         var entityConnectionStringBuilder = new EntityConnectionStringBuilder         {             Metadata = "res://*/School.csdl|res://*/School.ssdl|res://*/School.msl",             Provider = "System.Data.SqlClient",             ProviderConnectionString = connectionString         };         _schoolContext = new SchoolEntities(entityConnectionStringBuilder.ConnectionString);         _personRepository = new PersonRepository(this._schoolContext);     }     [FixtureTearDown]     public void FixtureTearDown()     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         _schoolContext.Dispose();     }     ...  As you can see, there is slightly more fixture setup code involved if your tests are using NDbUnit to provide the test data: Because we're dealing with a physical database instance here, we first need to pick up the test-specific connection string from the test assemblies' App.config, then initialize an NDbUnit helper object with this connection along with the provided xsd file, and also set up the SchoolEntities and the PersonRepository instances accordingly. The _database field (an instance of the INdUnitTest interface) will be our single access point to the underlying database: We use it to perform all the required operations against the data store. To have a flexible mechanism to easily insert data into the database, we can write a helper method like this: private void InsertTestData(params string[] dataFileNames) {     _database.PerformDbOperation(DbOperationFlag.DeleteAll);     if (dataFileNames == null)     {         return;     }     try     {         foreach (string fileName in dataFileNames)         {             if (!File.Exists(fileName))             {                 throw new FileNotFoundException(Path.GetFullPath(fileName));             }             _database.ReadXml(fileName);             _database.PerformDbOperation(DbOperationFlag.InsertIdentity);         }     }     catch     {         _database.PerformDbOperation(DbOperationFlag.DeleteAll);         throw;     } } This lets us easily insert test data from xml files, in any number and in a  controlled order (which is important because we eventually must fulfill referential constraints, or we must account for some other stuff that imposes a specific ordering on data insertion). Again, as with Typemock, I won't go into API details here. - Unfortunately, there isn't too much documentation for NDbUnit anyway, other than the already mentioned Quick Start Guide (and the source code itself, of course) - a not so uncommon problem with smaller Open Source Projects. Last not least, we need to provide the required test data in xml form. A snippet for data from the People table might look like this, for example: <?xml version="1.0" encoding="utf-8" ?> <School xmlns="http://tempuri.org/School.xsd">   <Person>     <PersonID>1</PersonID>     <LastName>Abercrombie</LastName>     <FirstName>Kim</FirstName>     <HireDate>1995-03-11T00:00:00</HireDate>   </Person>   <Person>     <PersonID>2</PersonID>     <LastName>Barzdukas</LastName>     <FirstName>Gytis</FirstName>     <EnrollmentDate>2005-09-01T00:00:00</EnrollmentDate>   </Person>   <Person>     ... You can also have data from various tables in one single xml file, if that's appropriate for you (but beware of the already mentioned ordering issues). It's true that your test assembly may end up with dozens of such xml files, each containing quite a big amount of text data. But because the files are of very low complexity, and with the help of a little bit of Copy/Paste and Excel magic, this appears to be well manageable. Executing some basic tests Here are some of the possible tests that can be written with the above preparations in place: private const string People = @"..\..\TestData\School.People.xml"; ... [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] public void GetNameList_ListOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.List);     Assert.Count(34, names);     Assert.AreEqual("Abercrombie, Kim", names.First());     Assert.AreEqual("Zheng, Roger", names.Last()); } [Test, MultipleAsserts, TestsOn("PersonRepository.GetNameList")] [DependsOn("RemovePerson_CalledOnce_DecreasesCountByOne")] public void GetNameList_NormalOrdering_ReturnsTheExpectedFullNames() {     InsertTestData(People);     List<string> names =         _personRepository.GetNameList(NameOrdering.Normal);     Assert.Count(34, names);     Assert.AreEqual("Alexandra Walker", names.First());     Assert.AreEqual("Yan Li", names.Last()); } [Test, TestsOn("PersonRepository.AddPerson")] public void AddPerson_CalledOnce_IncreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.AddPerson(new Person { FirstName = "Thomas", LastName = "Weller" });     Assert.AreEqual(count + 1, _personRepository.Count); } [Test, TestsOn("PersonRepository.RemovePerson")] public void RemovePerson_CalledOnce_DecreasesCountByOne() {     InsertTestData(People);     int count = _personRepository.Count;     _personRepository.RemovePerson(new Person { PersonID = 33 });     Assert.AreEqual(count - 1, _personRepository.Count); } Not much difference here compared to the corresponding Typemock versions, except that we had to do a bit more preparational work (and also it was harder to get the required knowledge). But this picture changes quite dramatically if we look at some more demanding test cases: Ok, and what if things are becoming somewhat more complex? Tests like the above ones represent the 'easy' scenarios. They may account for the biggest portion of real-world use cases of the application, and they are important to make sure that it is generally sound. But usually, all these nasty little bugs originate from the more complex parts of our code, or they occur when something goes wrong. So, for a testing strategy to be of real practical use, it is especially important to see how easy or difficult it is to mimick a scenario which represents a more complex or exceptional case. The following test, for example, deals with the case that there is some sort of invalid input from the caller: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] [Row(null, typeof(ArgumentNullException))] [Row("", typeof(ArgumentException))] [Row("NotExistingCourse", typeof(ArgumentException))] public void GetCourseMembers_WithGivenVariousInvalidValues_Throws(string courseTitle, Type expectedInnerExceptionType) {     var exception = Assert.Throws<RepositoryException>(() =>                                 _personRepository.GetCourseMembers(courseTitle));     Assert.IsInstanceOfType(expectedInnerExceptionType, exception.InnerException); } Apparently, this test doesn't need an 'Arrange' part at all (see here for the same test with the Typemock tool). It acts just like any other client code, and all the required business logic comes from the database itself. This doesn't always necessarily mean that there is less complexity, but only that the complexity happens in a different part of your test resources (in the xml files namely, where you sometimes have to spend a lot of effort for carefully preparing the required test data). Another example, which relies on an underlying 1-n relationship, might be this: [Test, MultipleAsserts, TestsOn("PersonRepository.GetCourseMembers")] public void GetCourseMembers_WhenGivenAnExistingCourse_ReturnsListOfStudents() {     InsertTestData(People, Course, Department, StudentGrade);     List<Person> persons = _personRepository.GetCourseMembers("Macroeconomics");     Assert.Count(4, persons);     Assert.ForAll(         persons,         @p => new[] { 10, 11, 12, 14 }.Contains(@p.PersonID),         "Person has none of the expected IDs."); } If you compare this test to its corresponding Typemock version, you immediately see that the test itself is much simpler, easier to read, and thus much more intention-revealing. The complexity here lies hidden behind the call to the InsertTestData() helper method and the content of the used xml files with the test data. And also note that you might have to provide additional data which are not even directly relevant to your test, but are required only to fulfill some integrity needs of the underlying database. Conclusion The first thing to notice when comparing the NDbUnit approach to its Typemock counterpart obviously deals with performance: Of course, NDbUnit is much slower than Typemock. Technically,  it doesn't even make sense to compare the two tools. But practically, it may well play a role and could or could not be an issue, depending on how much tests you have of this kind, how often you run them, and what role they play in your development cycle. Also, because the dataset from the required xsd file must fully match the database schema (even in parts that otherwise wouldn't be relevant to you), it can be quite cumbersome to be in a team where different people are working with the database in parallel. My personal experience is – as already said in the first part – that Typemock gives you a better development experience in a 'dynamic' scenario (when you're working in some kind of TDD-style, you're oftentimes executing the tests from your dev box, and your database schema changes frequently), whereas the NDbUnit approach is a good and solid solution in more 'static' development scenarios (when you need to execute the tests less frequently or only on a separate build server, and/or the underlying database schema can be kept relatively stable), for example some variations of higher-level integration or User-Acceptance tests. But in any case, opening Entity Framework based applications for testing requires a fair amount of resources, planning, and preparational work – it's definitely not the kind of stuff that you would call 'easy to test'. Hopefully, future versions of EF will take testing concerns into account. Otherwise, I don't see too much of a future for the framework in the long run, even though it's quite popular at the moment... The sample solution A sample solution (VS 2010) with the code from this article series is available via my Bitbucket account from here (Bitbucket is a hosting site for Mercurial repositories. The repositories may also be accessed with the Git and Subversion SCMs - consult the documentation for details. In addition, it is possible to download the solution simply as a zipped archive – via the 'get source' button on the very right.). The solution contains some more tests against the PersonRepository class, which are not shown here. Also, it contains database scripts to create and fill the School sample database. To compile and run, the solution expects the Gallio/MbUnit framework to be installed (which is free and can be downloaded from here), the NDbUnit framework (which is also free and can be downloaded from here), and the Typemock Isolator tool (a fully functional 30day-trial is available here). Moreover, you will need an instance of the Microsoft SQL Server DBMS, and you will have to adapt the connection strings in the test projects App.config files accordingly.

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  • 12c - flashforward, flashback or see it as of now...

    - by noreply(at)blogger.com (Thomas Kyte)
    Oracle 9i exposed flashback query to developers for the first time.  The ability to flashback query dates back to version 4 however (it just wasn't exposed).  Every time you run a query in Oracle it is in fact a flashback query - it is what multi-versioning is all about.However, there was never a flashforward query (well, ok, the workspace manager has this capability - but with lots of extra baggage).  We've never been able to ask a table "what will you look like tomorrow" - but now we do.The capability is called Temporal Validity.  If you have a table with data that is effective dated - has a "start date" and "end date" column in it - we can now query it using flashback query like syntax.  The twist is - the date we "flashback" to can be in the future.  It works by rewriting the query to transparently the necessary where clause and filter out the right rows for the right period of time - and since you can have records whose start date is in the future - you can query a table and see what it would look like at some future time.Here is a quick example, we'll start with a table:ops$tkyte%ORA12CR1> create table addresses  2  ( empno       number,  3    addr_data   varchar2(30),  4    start_date  date,  5    end_date    date,  6    period for valid(start_date,end_date)  7  )  8  /Table created.the new bit is on line 6 (it can be altered into an existing table - so any table  you have with a start/end date column will be a candidate).  The keyword is PERIOD, valid is an identifier I chose - it could have been foobar, valid just sounds nice in the query later.  You identify the columns in your table - or we can create them for you if they don't exist.  Then you just create some data:ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '123 Main Street', trunc(sysdate-5), trunc(sysdate-2) );1 row created.ops$tkyte%ORA12CR1>ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '456 Fleet Street', trunc(sysdate-1), trunc(sysdate+1) );1 row created.ops$tkyte%ORA12CR1>ops$tkyte%ORA12CR1> insert into addresses (empno, addr_data, start_date, end_date )  2  values ( 1234, '789 1st Ave', trunc(sysdate+2), null );1 row created.and you can either see all of the data:ops$tkyte%ORA12CR1> select * from addresses;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 123 Main Street                27-JUN-13 30-JUN-13      1234 456 Fleet Street               01-JUL-13 03-JUL-13      1234 789 1st Ave                    04-JUL-13or query "as of" some point in time - as  you can see in the predicate section - it is just doing a query rewrite to automate the "where" filters:ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate-3;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 123 Main Street                27-JUN-13 30-JUN-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  cthtvvm0dxvva, child number 0-------------------------------------select * from addresses as of period for valid sysdate-3Plan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!-3) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!-3)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 456 Fleet Street               01-JUL-13 03-JUL-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  26ubyhw9hgk7z, child number 0-------------------------------------select * from addresses as of period for valid sysdatePlan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.ops$tkyte%ORA12CR1> select * from addresses as of period for valid sysdate+3;     EMPNO ADDR_DATA                      START_DAT END_DATE---------- ------------------------------ --------- ---------      1234 789 1st Ave                    04-JUL-13ops$tkyte%ORA12CR1> @planops$tkyte%ORA12CR1> select * from table(dbms_xplan.display_cursor);PLAN_TABLE_OUTPUT-------------------------------------------------------------------------------SQL_ID  36bq7shnhc888, child number 0-------------------------------------select * from addresses as of period for valid sysdate+3Plan hash value: 3184888728-------------------------------------------------------------------------------| Id  | Operation         | Name      | Rows  | Bytes | Cost (%CPU)| Time     |-------------------------------------------------------------------------------|   0 | SELECT STATEMENT  |           |       |       |     3 (100)|          ||*  1 |  TABLE ACCESS FULL| ADDRESSES |     1 |    48 |     3   (0)| 00:00:01 |-------------------------------------------------------------------------------Predicate Information (identified by operation id):---------------------------------------------------   1 - filter((("T"."START_DATE" IS NULL OR              "T"."START_DATE"<=SYSDATE@!+3) AND ("T"."END_DATE" IS NULL OR              "T"."END_DATE">SYSDATE@!+3)))Note-----   - dynamic statistics used: dynamic sampling (level=2)24 rows selected.All in all a nice, easy way to query effective dated information as of a point in time without a complex where clause.  You need to maintain the data - it isn't that a delete will turn into an update the end dates a record or anything - but if you have tables with start/end dates, this will make it much easier to query them.

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